News for general public feed https://home.cern/ en The first accelerators are back in action https://home.cern/news/news/accelerators/first-accelerators-are-back-action <span>The first accelerators are back in action</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Corinne Pralavorio</div> </div> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span>Wed, 07/08/2020 - 12:11</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The CERN Control Centre is back in shift work mode, with walls of screens showing the status of the beams, and coffee flowing freely day and night. On Friday, 3 July, the <a href="https://home.cern/news/press-release/accelerators/lhc-prepares-new-achievements">Long Shutdown 2</a> accelerator coordination team handed over the key of the PS Booster to the accelerator operators. <a href="https://home.cern/science/accelerators/linear-accelerator-4">Linac 4</a> and the <a href="https://home.cern/science/accelerators/proton-synchrotron-booster">PS Booster</a> thus become the first two accelerators to be recommissioned, 18 months after the start of LS2.</p> <p>However, recommissioning will be far more complex than simply turning a key. When the operators handed the Booster over to the LS2 teams, they were driving a model built in the last century, and now they find themselves at the wheel of a completely transformed supercar. Work has been carried out on the engine (the power supply and power converters), the accelerator (the radiofrequency cavities), the steering (the magnets), the injection, the cooling circuit, the control and safety systems... in fact, a whole host of components have been replaced or upgraded (see below). “Around 40% of the machine has been replaced,” says David Hay, the “chief mechanic”, or engineer in charge of the coordination of LS2 activities at the PS Booster.</p> <p>The aims of the work on this nearly 50-year-old accelerator, forming part of the LHC Injector Upgrade (LIU) project, were twofold: to accelerate the particles arriving at higher energies from the brand new Linac 4 and to increase the brightness of, or the concentration of particles in, the beam.</p> <figure><a href="//cds.cern.ch/images/CERN-PHOTO-202007-095-1"><img alt="Handover,LS2,Coordination,Team,accelerator,PS,Recommissioning,Operation" src="//cds.cern.ch/images/CERN-PHOTO-202007-095-1/file?size=large" /></a> <figcaption>David Hay, who is responsible for LS2 coordination at the PS Booster, hands over a symbolic key to Bettina Mikulec, who leads the operations team for the PS Booster and Linac 4 (BE-OP-PSB). On the left, Julie Coupard, who is in charge of LS2 coordination for the injectors, and on the right, Gian Piero Di Giovanni, LIU project leader for the PS Booster, and Rende Steerenberg, Operations group leader (BE-OP) (Image: Maximilien Brice/CERN)</figcaption></figure><p><br /> Linac 4, the new first link in the chain, accelerates negative hydrogen ions (protons surrounded by two electrons) up to an energy of 160 MeV (compared to 50 MeV previously for the protons from Linac 2). The higher energy and the new injection system, which converts the H<sup>-</sup> ions into protons, increase the brightness by a factor of two. This means that a beam with the same dimensions will contain twice as many particles. In order to preserve this brightness in the PS, the next accelerator in the chain, the Booster will increase the energy up to 2 GeV (compared to 1.4 GeV previously), thanks to its all-new acceleration system. The electrical repulsion effect between particles of the same charge (Coulomb repulsion) lessens as the energy increases. To put it another way, higher energy helps keep the particles close together and thus contributes to maintaining the brightness. And with more brightness, comes more luminosity. “The Booster is key to increasing the luminosity of the LHC,” explains Gian Piero Di Giovanni, project leader for LIU at the PS Booster, “because it effectively determines the brightness of the beam.” The new injection mode with H<sup>-</sup> ions and a higher energy will also considerably reduce the particle loss rate. “We will lose only 1 to 2% at injection, compared to over 30% with the old system,” says Di Giovanni.</p> <p>The work at the Booster took 20 months above ground and 18 months underground. Despite the large scale of the renovations and the difficulties encountered with certain aspects of the civil-engineering work and of the cooling system for the RF cavities, not to mention lockdown, which froze activities for two months, the project has been completed on time. This achievement is down to the commitment of the teams and meticulous and proactive coordination.</p> <p>Commissioning of some of the new systems started several weeks ago. The operators are now taking charge with new, cutting-edge control software. “We have spent the past two years developing the integration of these new systems,” emphasises Bettina Mikulec, who supervises the operation of the Booster and Linac 4. “We now need to implement and test all the subsystems from the Control Centre and get them working in harmony.” This complex commissioning process will take several months, initially without any beam. Whereas Linac 4 will resume tests with beam this summer, the first particles should be circulating in the PS Booster right at the end of the year.</p> <p><strong>The metamorphosis of the Booster</strong></p> <ul><li><strong>Power supply:</strong> A new power supply system, similar to the one that was installed for the PS (<a href="https://cds.cern.ch/record/1265859?ln=en">POPS</a>), based on power converters and capacitors and known as POPS-B, has been installed in a new building above ground. The power converters will supply the magnets with electrical intensities of 5500 amps, compared with 4000 amps previously. Over 95% of the Booster’s power converters have been replaced since Long Shutdown 1. Some 318 new converters, ranging from 1 kW to several MW, supply all the components of the accelerator.</li> <li><strong>Cooling:</strong> The Booster has a new cooling system, with cooling towers in two renovated buildings.</li> <li><strong>Injection and ejection:</strong> To cope with the increase in energy and the use of negative hydrogen ions at injection, the transfer lines from Linac 4 to the Booster and from the Booster to the PS have all been replaced. This includes new magnets (kickers, septa, dipoles, quadrupoles and correctors), new instrumentation and new beam dumps. Since it comprises four superimposed rings, the Booster requires a particularly sophisticated particle <a href="https://home.cern/news/news/accelerators/new-magnets-feed-proton-synchrotron-booster">distribution system</a>.</li> <li><strong>Acceleration:</strong> The new acceleration system is composed of three structures, each housing <a href="https://home.cern/news/news/accelerators/new-acceleration-system-ps-booster">eight cavities built using a magnetic material known as FineMet</a>.</li> <li><strong>Magnets:</strong> In the transfer lines and the Booster ring itself, around 60 magnets have been replaced or renovated.</li> <li><strong>Safety and instrumentation:</strong> A whole host of new sensors, beam position monitors, beam loss monitors, wire scanners, etc. have been installed to monitor and measure the particle beams. Devices to stop the beam or particles that stray from the trajectory have been added to the ring. Among these, a collimation system known as an “absorber/scraper”, is the latest device to be installed in the Booster. The role of these devices is even more crucial now that the beam is denser.</li> </ul><p>Watch the <a class="bulletin" href="https://www.instagram.com/tv/CCBRPAxIlvz/?utm_source=ig_embed&amp;utm_campaign=loading">Instagram Live session</a> filmed in the PS Booster just before the accelerator was closed.</p> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Wed, 08 Jul 2020 10:11:06 +0000 cmenard 155365 at https://home.cern LHCb discovers a new type of tetraquark at CERN https://home.cern/news/news/physics/lhcb-discovers-new-type-tetraquark-cern <span>LHCb discovers a new type of tetraquark at CERN</span> <span><span lang="" about="/user/147" typeof="schema:Person" property="schema:name" datatype="">cagrigor</span></span> <span>Tue, 06/30/2020 - 17:23</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2722354" data-filename="Tetraquark_LHCb_2019_large%20(00050)-3" id="CERN-HOMEWEB-PHO-2020-073-1"> <a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-073-1" title="View on CDS"> <img alt="Illustration of a tetraquark composed of two charm quarks and two charm antiquarks, detected for the first time by the LHCb collaboration at CERN." src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-073-1/file?size=medium"/> </a> <figcaption> Illustration of a tetraquark composed of two charm quarks and two charm antiquarks, detected for the first time by the LHCb collaboration at CERN. <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The LHCb collaboration has observed a type of four-quark particle never seen before. The discovery, presented at a recent seminar at CERN and described in a <a class="bulletin" href="https://arxiv.org/abs/2006.16957">paper</a> posted today on the arXiv preprint server, is likely to be the first of a previously undiscovered class of particles.</p> <p>The finding will help physicists better understand the complex ways in which quarks bind themselves together into composite particles such as the ubiquitous protons and neutrons that are found inside atomic nuclei.</p> <p>Quarks typically combine together in groups of twos and threes to form particles called hadrons. For decades, however, theorists have predicted the existence of four-quark and five-quark hadrons, which are sometimes described as tetraquarks and pentaquarks, and in recent years experiments including LHCb have confirmed the existence of several of these exotic hadrons.<em> </em>These particles made of unusual combinations of quarks are an ideal “laboratory” for studying one of the four known fundamental forces of nature, the strong interaction that binds protons, neutrons and the atomic nuclei that make up matter. Detailed knowledge of the strong interaction is also essential for determining whether new, unexpected processes are a sign of new physics or just standard physics.</p> <p>“Particles made up of four quarks are already exotic, and the one we have just discovered is the first to be made up of four heavy quarks of the same type, specifically two charm quarks and two charm antiquarks,” says the outgoing spokesperson of the LHCb collaboration, Giovanni Passaleva. “Up until now, LHCb and other experiments had only observed tetraquarks with two heavy quarks at most and none with more than two quarks of the same type.”</p> <p>“These exotic heavy particles provide extreme and yet theoretically fairly simple cases with which to test models that can then be used to explain the nature of ordinary matter particles, like protons or neutrons. It is therefore very exciting to see them appear in collisions at the LHC for the first time,” explains the incoming LHCb spokesperson, Chris Parkes.</p> <p>The LHCb team found the new tetraquark using the particle-hunting technique of looking for an excess of collision events, known as a “bump”, over a smooth background of events. Sifting through the full LHCb datasets from the first and second runs of the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider</a>, which took place from 2009 to 2013 and from 2015 to 2018 respectively, the researchers detected a bump in the mass distribution of a pair of J/ψ particles, which consist of a charm quark and a charm antiquark. The bump has a statistical significance of more than five standard deviations, the usual threshold for claiming the discovery of a new particle, and it corresponds to a mass at which particles composed of four charm quarks are predicted to exist.</p> <p>As with previous tetraquark discoveries, it is not completely clear whether the new particle is a “true tetraquark”, that is, a system of four quarks tightly bound together, or a pair of two-quark particles weakly bound in a molecule-like structure. Either way, the new tetraquark will help theorists test models of quantum chromodynamics, the theory of the strong interaction.</p> <p>______</p> <p><em>Read more on the <a href="https://lhcb-public.web.cern.ch/Welcome.html#Tcccc">LHCb website</a>.</em></p> </div> Tue, 30 Jun 2020 15:23:10 +0000 cagrigor 155300 at https://home.cern White Rabbit, a CERN-born technology, sets a new global standard https://home.cern/news/news/knowledge-sharing/white-rabbit-cern-born-technology-sets-new-global-standard <span>White Rabbit, a CERN-born technology, sets a new global standard</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Marzena Lapka</div> </div> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Fri, 06/26/2020 - 16:13</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><a href="https://cern.ch/white-rabbit">White Rabbit</a> (WR) is a technology developed at CERN to provide the LHC accelerator chain with deterministic data transfer, sub-nanosecond accuracy and a synchronisation precision of a few picoseconds. First used in 2012, the technology has since then expanded its applications outside the field of particle physics and is now deployed in <a href="https://www.ohwr.org/project/white-rabbit/wikis/WRUsers">numerous scientific infrastructures</a> worldwide. It has shown its innovative potential by being commercialised and introduced into different industries, including telecommunications, financial markets, smart grids, the space industry and quantum computing.</p> <p>CERN developed WR as an open-source hardware and it was initially adopted by other research infrastructures with similar challenges in highly accurate synchronisation of distributed electronic devices. The R&amp;D process and all the knowledge gained throughout its development have been made available <a href="https://ohwr.org/project/white-rabbit/wikis/home">through CERN’s Open Hardware Repository</a>. This gives other organisations and companies the freedom to use and modify existing developments. Through the proactive engagement of CERN’s <a href="https://kt.cern/">Knowledge Transfer</a> and <a href="https://be-dep-co.web.cern.ch/">Beam Controls</a> groups, a larger group of companies and organisations contributed to the development of hardware, software, and gateware for WR switches and nodes. The WR ecosystem quickly grew to include several organisations, developing open hardware for widespread benefit. This collaborative approach brought improvements to the original concept, allowing CERN to also benefit from the new developments.</p> <p>On 16 June, the WR technology was recognised by being included in the worldwide industry standard called <a href="https://standards.ieee.org/standard/1588-2019.html">Precision Time Protocol</a> (PTP), governed by the <a href="https://www.ieee.org/">IEEE</a>, the world’s largest technical professional organisation dedicated to advancing technology for the benefit of humanity. The WR addition to the PTP standard, referred to as High Accuracy, increases PTP’s synchronisation performance by a few orders of magnitude, from sub-microsecond to sub-nanosecond.</p> <p>“PTP is the first IEEE standard to incorporate a CERN-born technology. This is a major step for White Rabbit. It is already widely used in large scientific facilities and its adoption in industry is gaining momentum. Its incorporation into the PTP standard will allow hardware vendors world-wide to produce WR equipment compliant with the PTP standard and consequently accelerate its dissemination on a larger scale,” says Maciej Lipinski, an electronics engineer at CERN, who led the <a href="https://ohwr.org/project/wr-std/wikis/home">WR standardisation effort</a>.</p></div> Fri, 26 Jun 2020 14:13:18 +0000 thortala 155119 at https://home.cern Electricity transmission reaches even higher intensities https://home.cern/news/news/accelerators/electricity-transmission-reaches-even-higher-intensities <span>Electricity transmission reaches even higher intensities</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Corinne Pralavorio</div> </div> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span>Wed, 06/24/2020 - 15:26</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Intensity is rising at CERN. In the superconducting equipment testing hall, an innovative transmission line has set a new record for the transport of electricity. The link, which is 60 metres long, has transported a total of 54 000 amperes (54 kA, or 27 kA in either direction). “It is the most powerful electrical transmission line built and operated to date!” says Amalia Ballarino, the designer and project leader.</p> <p>The line has been developed for the <a href="https://home.cern/science/accelerators/high-luminosity-lhc">High-Luminosity LHC (HL-LHC)</a>, the accelerator that will succeed the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider (LHC)</a> and is scheduled to start up at the end of 2027. Links like this one will connect the HL-LHC’s magnets to the power converters that supply them.</p> <figure class="cds-video" id="CERN-FOOTAGE-2020-012-001"><div><iframe allowfullscreen="true" frameborder="0" height="450" src="//cds.cern.ch/video/CERN-FOOTAGE-2020-012-001" width="100%"></iframe></div> <figcaption>Interview with Amalia Ballarino, the superconducting link project leader, during the insertion of the line into its cryostat in February 2020 <span>(Video: CERN)</span></figcaption></figure><div id="vidyowebrtcscreenshare_is_installed">The secret to the new line’s power can be summarised in one word: <a href="https://home.cern/science/engineering/superconductivity">superconductivity</a>. <p>The line is composed of cables made of magnesium diboride (MgB<sub>2</sub>), which is a superconductor and therefore presents no resistance to the flow of the current and can transmit much higher intensities than traditional non-superconducting cables. On this occasion, the line transmitted an intensity 25 times greater than could have been achieved with copper cables of a similar diameter. Magnesium diboride has the added benefit that it can be used at 25 kelvins (-248 °C), a higher temperature than is needed for conventional superconductors. This superconductor is more stable and requires less cryogenic power. The superconducting cables that make up the innovative line are inserted into a flexible cryostat, in which helium gas circulates.</p> <p>The strands of magnesium diboride of which the cables are made were developed by industry, under CERN’s supervision. The cable manufacturing process was designed at CERN, before industrial production began. As the strands of magnesium diboride are fragile, manufacturing the cables requires considerable expertise. The current is transmitted from the power supply at room temperature to the flexible link by ReBCO high-temperature superconducting (HTS) cables.</p> <figure class="cds-image align-left" id="CERN-HOMEWEB-PHO-2020-070-2"><a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-070-2" title="View on CDS"><img alt="home.cern,Accelerators" src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-070-2/file?size=large" /></a> <figcaption>A team member connects the superconducting link cables before the electrical transmission tests begin<span> (Image: CERN)</span></figcaption></figure><p>Last year, <a href="https://home.cern/news/news/accelerators/successful-tests-cooler-way-transport-electricity">an initial prototype transmitted a 40 kA intensity over a distance of 60 metres</a>. The link that is currently being tested is the forerunner of the final version that will be installed in the accelerator. It is composed of 19 cables that supply the various magnet circuits and could transmit intensities of up to 120 kA! “We started the power tests by connecting just four cables, two at 20 kA and two at 7 kA,” explains Amalia Ballarino. New records are therefore expected to be set in the coming months.</p> <p>This new type of electrical transmission line has applications far beyond the realm of fundamental research. Links like these, which can transfer vast amounts of current within a small diameter, could be used to deliver electricity in big cities, for example, or to connect renewable energy sources to populated areas.</p> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Wed, 24 Jun 2020 13:26:15 +0000 cmenard 155109 at https://home.cern Graphene’s potential to improve magnetic measurements for accelerators https://home.cern/news/news/engineering/graphenes-potential-improve-magnetic-measurements-accelerators <span>Graphene’s potential to improve magnetic measurements for accelerators</span> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Tue, 06/23/2020 - 16:02</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>CERN and Paragraf – a technology company borne out of the department of materials science at the University of Cambridge – are set to detail final results of tests conducted on a novel graphene-based local magnetic measurement sensor. The collaboration has proved that such a sensor eliminates some of the systematic errors and inaccuracies found in the state-of-the-art sensors used at CERN.</p> <p>The Hall probe is an important tool for local magnetic field mapping – an essential task in particle accelerators, which depend on high-precision magnetic fields. The probe transduces the magnetic field into a proportional voltage. However, errors frequently arise due to elements of the sensor not being perfectly aligned and sensitive to in-plane field components (planar effect), as well as non-linear response.</p> <p>Theoretically, graphene solves this issue. This carbon allotrope, first discovered at the University of Manchester in 2004, has been hailed as the new wonder material, as its extreme thinness, lightness, conductivity and resistance could revolutionize a variety of technologies. In the case of the Hall probe, the development of a two-dimensional graphene sensor clears the issue of planar effects and makes for precise detections, including at liquid-helium temperatures.</p> <p><em>_____</em></p> <p><em>Find out more in the </em><a class="bulletin" href="https://cerncourier.com/a/graphene-trialled-for-magnetic-measurements/">CERN Courier</a><em>.</em></p> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Tue, 23 Jun 2020 14:02:09 +0000 thortala 155100 at https://home.cern NA64 explores gap in searches for axions and axion-like particles https://home.cern/news/news/physics/na64-explores-gap-searches-axions-and-axion-particles <span>NA64 explores gap in searches for axions and axion-like particles</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Ana Lopes</div> </div> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span>Mon, 06/22/2020 - 15:44</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>There is strong evidence that <a href="/science/physics/dark-matter">dark matter</a> exists and permeates the cosmos, yet all searches for the hypothetical particles that may make up this invisible form of matter have drawn a blank so far. In light of these null results, researchers have started to spread a wider net in their searches, exploring as many types of particle as possible, new regions in which the particles may lie hidden and new ways to probe them. The NA64 experiment collaboration has now widened the scope of its searches with a <a href="https://arxiv.org/abs/2005.02710v2">search for axions and axion-like particles</a> – hypothetical particles that could mediate an interaction between dark matter and visible matter or comprise dark matter itself, depending on their exact properties.</p> <p>The NA64 team targeted an unexplored area for axions and axion-like particles, a gap in the two-dimensional area of possible values of their mass and interaction strength with a pair of photons. This gap doesn’t include the regions where axions and axion-like particles could make up dark matter, but it includes an area where axions could explain the long-puzzling symmetry properties of the strong force, for which axions were originally proposed, as well as an area where axion-like particles could mediate an interaction between dark matter and visible matter.</p> <p>To explore this gap, the NA64 team used an electron beam of 100 GeV energy from the <a href="/science/accelerators/super-proton-synchrotron">Super Proton Synchrotron</a> and directed it onto a fixed target. They then searched for axions and axion-like particles that would be produced in interactions between high-energy photons generated by the 100 GeV electrons in the target and virtual photons from the target’s atomic nuclei. The researchers looked for the particles both through their transformation, or “decay”, into a pair of photons in a detector placed right after the target and through the “missing energy” that the particles would carry away if they decayed downstream of the detector.</p> <p>The NA64 team analysed data that was collected over the course of three years, between 2016 and 2018. Together, these data corresponded to some three hundred billion electrons hitting the target. The NA64 researchers found no sign of axions or axion-like particles in this dataset, but the null result allowed them to set limits on the allowed values of the interaction strength of axions and axion-like particles with two photons for particle masses below 55 MeV.</p> <p>“We’re very excited to have added NA64 to the list of experiments that are hunting for axions as well as axion-like particles, which are a popular candidate for a mediator of a new force between visible and dark matter”, says NA64 collaboration spokesperson Sergei Gninenko. “Little by little, and together, these experiments are narrowing down the regions of where to look for, and perhaps find, these particles.”</p> </div> Mon, 22 Jun 2020 13:44:44 +0000 abelchio 155093 at https://home.cern A CERN-led international collaboration develops 3D-printed neutrino detectors https://home.cern/news/news/experiments/cern-led-international-collaboration-develops-3d-printed-neutrino-detectors <span>A CERN-led international collaboration develops 3D-printed neutrino detectors </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Thomas Hortala</div> </div> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Mon, 06/22/2020 - 13:52</span> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">Example of a plastic Scintillator detector (left) and a stage of its 3D-printing process (right)</div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Plastic scintillators are one of the most used active materials in high-energy physics. Their properties make it possible to track and distinguish between particle topologies. Among other things, scintillators are used in the detectors of neutrino oscillation experiments, where they reconstruct the final state of the neutrino interaction. Measurements of oscillation phenomena are carried out through comparison of observations of neutrinos in near detectors (close to the target) and far detectors (up to several hundred kilometres away).</p> <p>CERN is strongly involved in the T2K experiment, the current world-leading neutrino oscillation experiment, in Japan, which recently <a href="https://t2k-experiment.org/2020/04/t2k-results-restrict-possible-values-of-neutrino-cp-phase/">released promising results</a>. A future upgrade of the experiment’s near detector will pave the way for more precise results. The novel detector will comprise a two-tonne polystyrene-based plastic scintillator detector segmented into 1 x 1 x 1 cm<sup>3</sup> cubes, leading to a total of around two million sensitive elements: the smaller the cubes, the more precise the results. This technology could be adopted for other projects, such as the DUNE near detector. However, more precise measurements would require finer granularity, making the detector assembly harder.</p> <p>This is where the CERN EP-Neutrino group – led by Albert De Roeck – steps in, developing a new plastic scintillator production technique that involves additive manufacturing. The R&amp;D is carried out in collaboration with the Institute for Scintillation Materials (ISMA) of the National Academy of Science of Ukraine, which has strong expertise in the development of scintillator materials, and the <em>Haute </em><em>É</em><em>cole d’Ing</em><em>é</em><em>nierie et Gestion du Canton de Vaud</em> (HEIG-VD), which is expert in additive manufacturing. The final goal is to 3D-print a “super-cube”, that is, a single massive block of scintillator containing many optically independent cubes. 3D-printing would solve the issue of assembling the individual cubes, which could thus be produced in any size, including smaller than 1 cm<sup>3</sup>, and relatively quickly (volumes bigger than 20 x 20 x 20 cm<sup>3</sup> can be produced in about a day).</p> <p>So far, the collaboration has been fruitful. A preliminary test gave the first proof of concept: the scintillation light yield of a polystyrene-based scintillator 3D-printed with fused deposition modelling (see right fig.) has been found to be comparable to that of a traditional scintillator. But the road towards a ready-to-use super-cube is still long. Further optimisation of the scintillator parameters and tuning of the 3D-printer configuration, followed by a full characterisation of the 3D-printed scintillator, will need to be achieved before the light reflector material for optically isolating the cubes can be developed.</p> <p>This new technique could also open up new possibilities for the field of particle detection. A successful 3D-printed plastic scintillator detector could pave the way for a broader use of this technology in detector building, which could shake up the field of high-energy physics, as well as that of medicine, where particle detectors are used, for instance, in cancer therapy. Moreover, the greatly cost-effective 3D-printer could be replicated quite easily and used in a vast number of settings. Umut Kose, from the EP-neutrino group and Neutrino Platform at CERN, explains: “Our dream goes beyond the super-cube. We like to think that, in a few years, 3D-printing will allow high-school students to make their own radiation detection systems. The outreach potential of this technology is mind-blowing”.</p> <p>Davide Sgalaberna, now at ETH Zurich, cannot hide his enthusiasm for this adventure: “This is the first time that 3D-printing could be used for real particle detectors. We are transforming our personal will into a project, and we are hopeful that this could lead to a breakthrough. That is thrilling”. A thrill shared by Davide’s colleagues, who are more than ready to resume work on the 3D-printed detector once the easing of lockdown allows everyone to return to CERN.</p> <p>_____</p> <p><em>Read the full story <a class="bulletin" href="https://ep-news.web.cern.ch/content/using-3d-printing-techniques-future-neutrino-detectors">in the EP newsletter</a>.</em></p> </div> Mon, 22 Jun 2020 11:52:19 +0000 thortala 155088 at https://home.cern Particle physicists update strategy for the future of the field in Europe https://home.cern/news/news/physics/particle-physicists-update-strategy-future-field-europe <span>Particle physicists update strategy for the future of the field in Europe</span> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span>Fri, 06/19/2020 - 10:26</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Following almost two years of discussion and deliberation, the CERN Council today announced that it has updated <a href="https://home.cern/sites/home.web.cern.ch/files/2020-06/2020%20Update%20European%20Strategy.pdf">the strategy that will guide the future of particle physics in Europe</a> within the global particle-physics landscape. Presented during the open part of the Council’s meeting, held remotely due to the ongoing COVID-19 pandemic, the recommendations highlight the scientific impact of particle physics, as well as its technological, societal and human capital.</p> <p>By probing ever-higher energy and thus smaller distance scales, particle physics has made discoveries that have transformed the scientific understanding of the world. Nevertheless, many of the mysteries about the universe, such as the nature of <a href="https://home.cern/science/physics/dark-matter">dark matter</a>, and the <a href="https://home.cern/science/physics/antimatter">preponderance of matter over antimatter</a>, are still to be explored. The 2020 update of the <a href="https://europeanstrategy.cern/">European Strategy for Particle Physics</a> proposes a vision for both the near- and the long-term future of the field, which maintains Europe's leading role in addressing the outstanding questions in particle physics and in the innovative technologies being developed within the field.</p> <p>The highest scientific priorities identified in this update are the study of the <a href="https://home.cern/science/physics/higgs-boson">Higgs boson</a> - a unique particle that raises scientific profound questions about the fundamental laws of nature - and the exploration of the high-energy frontier. These are two crucial and complementary ways to address the open questions in particle physics.</p> <p>“The Strategy is above all driven by science and thus presents the scientific priorities for the field,” says Ursula Bassler, President of the CERN Council. “The European Strategy Group (ESG) – a special body set up by the Council – successfully led a strategic reflection to which several hundred European physicists contributed.” The scientific vision outlined in the Strategy should serve as a guideline to CERN and facilitate a coherent science policy across Europe.</p> <p>The successful completion of the <a href="https://home.cern/science/accelerators/high-luminosity-lhc">High-Luminosity LHC</a> in the coming decade, for which upgrade work is currently in progress at CERN, should remain the focal point of European particle physics. The strategy emphasises the importance of ramping up research and development (R&amp;D) for advanced accelerator, detector and computing technologies, as a necessary prerequisite for all future projects. Delivering the near and long-term future research programme envisaged in this Strategy update requires both focused and transformational R&amp;D, which also has many potential benefits to society.</p> <p>The document also highlights the need to pursue an electron-positron collider acting as a “Higgs factory” as the highest-priority facility after the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider</a> (LHC). The <a href="https://home.cern/news/series/lhc-physics-ten/higgs-boson-what-makes-it-special">Higgs boson was discovered at CERN in 2012</a> by scientists working on the LHC, and is expected to be a powerful tool to look for physics beyond the Standard Model. Such a machine would produce copious amounts of Higgs bosons in a very clean environment, would make dramatic progress in mapping the diverse interactions of the Higgs boson with other particles and would form an essential part of a rich research programme, allowing measurements of extremely high precision. Operation of this future collider at CERN could begin within a timescale of less than 10 years after the full exploitation of the High-Luminosity LHC, which is expected to complete operations in 2038.</p> <p>The exploration of significantly higher energies than the LHC will allow new discoveries to be made and the answers to existing mysteries, such as the <a href="https://home.cern/science/physics/dark-matter">nature of dark matter</a>, to potentially be found. In acknowledgement of the fact that the particle physics community is ready to prepare for the next step towards even higher energies and smaller scales, another significant recommendation of the Strategy is that Europe, in collaboration with the worldwide community, should undertake a technical and financial feasibility study for a next-generation hadron collider at the highest achievable energy, with an electron-positron collider as a possible first stage.</p> <p>It is further recommended that Europe continue to support neutrino projects in Japan and the US. Cooperation with neighbouring fields is also important, such as astroparticle and nuclear physics, as well as continued collaboration with non-European countries.</p> <p>“This is a very ambitious strategy, which outlines a bright future for Europe and for CERN with a prudent, step-wise approach. We will continue to invest in strong cooperative programmes between CERN and other research institutes in CERN’s Member States and beyond,” declares CERN Director-General Fabiola Gianotti. “These collaborations are key to sustained scientific and technological progress and bring many societal benefits.”</p> <p>“The natural next step is to explore the feasibility of the high-priority recommendations, while continuing to pursue a diverse programme of high-impact projects,” explains ESG chair Halina Abramowicz. “Europe should keep the door open to participating in other headline projects that will serve the field as a whole, such as the proposed International Linear Collider project.”</p> <p>Beyond the immediate scientific return, major research infrastructures such as CERN have broad <a href="https://home.cern/about/what-we-do/our-impact">societal impact</a>, thanks to their technological, economic and human capital.<strong> </strong>Advances in accelerators, detectors and computing have a significant impact on areas like <a href="https://kt.cern/medtech">medical and biomedical technologies</a>, <a href="https://kt.cern/aerospace">aerospace applications</a>, <a href="https://kt.cern/cern-technologies-society">cultural heritage, artificial intelligence, energy, big data and robotics</a>. Partnerships with large research infrastructures help drive innovation in industry. In terms of human capital, the training of early-career scientists, engineers, technicians and professionals provides a talent pool for industry and other fields of society.  </p> <p>The Strategy also highlights two other essential aspects: the environment and the importance of Open Science. “The environmental impact of particle physics activities should continue to be carefully studied and minimised. A detailed plan for the minimisation of environmental impact and for the saving and reuse of energy should be part of the approval process for any major project,” says the report. The technologies developed in particle physics to minimise the environmental impact of future facilities may also find more general applications in environmental protection.</p> <p>The update of the European Strategy for Particle Physics announced today <a href="https://home.cern/news/press-release/cern/european-particle-physics-community-gears-new-shared-vision-future">got under way in September 2018</a>, when the CERN Council, comprising representatives from CERN’s Member and Associate Member States, established a European Strategy Group (ESG) to coordinate the process. The ESG worked in close consultation with the scientific community. Nearly two hundred submissions were discussed during an <a href="https://home.cern/news/press-release/knowledge-sharing/granada-european-particle-physics-community-prepares-decisions">Open Symposium in Granada in May 2019</a> and distilled into the <a href="https://home.cern/news/news/cern/briefing-book-2020-update-european-strategy-particle-physics">Physics Briefing Book</a>, a scientific summary of the community’s input, prepared by the Physics Preparatory Group. The ESG converged on the final recommendations during a week-long <a href="https://home.cern/news/news/knowledge-sharing/particle-physicists-formulate-future-field">drafting session held in Germany in January 2020</a>. The group’s findings were presented to the CERN Council in March and were scheduled to be announced on 25 May, in Budapest. This was delayed due to the global Covid-19 situation but they have now been made publicly available.</p> <p>For more information:</p> <ul><li>Read the<a href="https://cerncourier.com/a/european-strategy-update-unveils-ambitious-future/"> feature article in the CERN Courier</a>.</li> <li>Consult the documents of the Update of the European Strategy for Particle Physics: <ul><li><a class="bulletin" href="https://cds.cern.ch/record/2720129/files/Update%20European%20Strategy.pdf">2020 Update of the European Strategy for Particles Physics</a></li> <li><a class="bulletin" href="https://cds.cern.ch/record/2720131/files/Deliberation%20European%20Strategy.pdf">Deliberation Document on the 2020 Update of the European Strategy for Particle Physics</a></li> </ul></li> </ul></div> Fri, 19 Jun 2020 08:26:26 +0000 cmenard 155074 at https://home.cern Estonia to become Associate Member in the Pre-Stage to Membership of CERN https://home.cern/news/press-release/cern/estonia-become-associate-member-pre-stage-membership-cern <span>Estonia to become Associate Member in the Pre-Stage to Membership of CERN</span> <span><span lang="" about="/user/147" typeof="schema:Person" property="schema:name" datatype="">cagrigor</span></span> <span>Thu, 06/18/2020 - 15:15</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2721221" data-filename="202006-088_%209" id="CERN-PHOTO-202006-088-6"> <a href="//cds.cern.ch/images/CERN-PHOTO-202006-088-6" title="View on CDS"> <img alt="Remote Signature of the Agreement concerning the granting of the status of Associate Member in the pre-stage to Membership of CERNof the Republic of Estonia byHis Excellency Mr Jüri RatasPrime MinisterRepublic of EstoniaFriday, 19June 2020" src="//cds.cern.ch/images/CERN-PHOTO-202006-088-6/file?size=medium"/> </a> <figcaption> Remote Signature of the Agreement concerning the granting of the status of Associate Member in the pre-stage to Membership of CERNof the Republic of Estonia byHis Excellency Mr Jüri RatasPrime MinisterRepublic of EstoniaFriday, 19June 2020 <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Geneva, 19 June 2020. Today, the representatives of CERN and of the Government of Estonia signed an Agreement admitting Estonia as an Associate Member in the Pre-Stage to Membership of CERN. Due to the COVID-19 pandemic, the signing ceremony took place via a live feed between Geneva and Tallinn, a first in the 66-year history of CERN. The Agreement will enter into force once CERN has been informed by the Estonian authorities that all the necessary approval processes have been finalised.</p> <p>“We are very pleased to welcome Estonia as a new Associate Member State in the Pre-Stage to Membership. Over the years, Estonian scientists have contributed significantly to CERN’s scientific activities and have actively participated in CERN’s educational programmes” said Fabiola Gianotti, CERN Director-General. “With Estonia becoming an Associate Member, Estonia and CERN will have the opportunity to expand their collaboration in, and increase their mutual benefit from, scientific and technological development as well as education and training activities. We are looking forward to strengthening our ties further.”</p> <p>“Mutually beneficial cooperation with CERN is important for Estonia. Becoming an associate member is the next big step for Estonia to deepen its co-operation with CERN before becoming a full member. As an associate member, many important opportunities open up for Estonian entrepreneurs, scientists and researchers to work together on innovation and R&amp;D, which will greatly benefit Estonia’s business sector and the economy as a whole and, vice versa, we can also share our experiences and I am convinced that CERN will become a valued partner for Estonia and Estonia a valued partner for CERN,” said Jüri Ratas, Estonia’s Prime Minister, at the signing ceremony.</p> <p>Estonia’s co-operation with CERN was established in 1996. After joining the <a href="http://public.web.cern.ch/public/en/LHC/CMS-en.html">CMS</a> experiment at the Large Hadron Collider – CERN’s flagship accelerator – in 1997, Estonia became an active member of the CERN community. Between 2004 and 2016, new collaboration frameworks gradually boosted scientific and technical co-operation between Estonia and CERN and further strengthened the participation of the Estonian particle physics community in the high-energy physics experiments at CERN. In September 2018 Estonia applied for CERN Membership.</p> <p>Today, Estonia is represented by 25 scientists at CERN, namely an active group of theorists, researchers involved in R&amp;D for the <a href="http://clic-study.web.cern.ch/">CLIC</a> project and a CMS team involved in data analysis and the Worldwide LHC Computing Grid (<a href="https://home.cern/science/computing/worldwide-lhc-computing-grid">WLCG</a>), with Estonia operating one of the Tier-2 centres in Tallinn; another team is taking part in the <a href="http://public.web.cern.ch/public/en/LHC/TOTEM-en.html">TOTEM</a> experiment. All these scientists represent the following institutes: the Estonian National Institute of Chemical Physics and Biophysics, the University of Tartu and its Institute of Physics, the Technical University of Tallinn (TalTech) and the Observatory of Tartu.</p> <p>Estonia also benefits from CERN’s educational activities through the regular participation of its students and high-school teachers in the Summer Student and High-School Teacher programmes.</p> <p>CERN’s Associate Member States are entitled to participate in the meetings of the CERN Council, Finance Committee and Scientific Policy Committee. Their nationals are eligible for limited-duration staff positions and fellowships and their industry is entitled to bid for CERN contracts, increasing opportunities for industrial collaboration in advanced technologies.</p> <p><strong>Footnote(s)</strong></p> <p>1. CERN, the European Organization for Nuclear Research, is one of the world's leading laboratories for particle physics. The Organization is located on the French-Swiss border, with its headquarters in Geneva. Its Member States are: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Spain, Sweden, Switzerland and United Kingdom. Cyprus and Slovenia are Associate Member States in the pre-stage to Membership. Croatia, India, Lithuania, Pakistan, Turkey and Ukraine are Associate Member States. The European Union, Japan, JINR, the Russian Federation, UNESCO and the United States of America currently have Observer status.</p></div> Thu, 18 Jun 2020 13:15:58 +0000 cagrigor 155054 at https://home.cern High-school teams from Switzerland and Germany win CERN Beamline for Schools competition https://home.cern/news/press-release/cern/high-school-teams-switzerland-and-germany-win-cern-beamline-schools <span>High-school teams from Switzerland and Germany win CERN Beamline for Schools competition</span> <span><span lang="" about="/user/18835" typeof="schema:Person" property="schema:name" datatype="">mailys</span></span> <span>Mon, 06/15/2020 - 10:33</span> <div class="field field--name-field-p-news-display-listing-img field--type-image field--label-hidden field--item"> <img src="/sites/home.web.cern.ch/files/2020-06/bl4s2.jpg" width="1219" height="1082" alt="CERN Beamline for Schools 2020 winners" typeof="foaf:Image" class="img-responsive" /> </div> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">Winners of the CERN Beamline for Schools 2020: Team ChDR Cheese (above) from the Werner-von-Siemens-Gymnasium in Berlin, Germany, and Team Nations&#039; Flying Foxes (below) from the International School of Geneva, Switzerland.</div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Geneva and Hamburg, 15 June 2020. Two teams of high-school students, one from the <a href="https://www.ecolint.ch/campus/campus-des-nations">International School of Geneva, Campus des Nations</a>, Switzerland, and one from the <a href="https://www.siemens-gymnasium-berlin.de/">Werner-von-Siemens-Gymnasium</a> in Berlin, Germany, have won the 2020 <a href="http://beamline-for-schools.web.cern.ch/">Beamline for Schools competition</a> (BL4S). Later this year, the winning teams will be invited to the <a href="http://www.desy.de/index_eng.html">DESY</a> research centre in Hamburg, Germany, for the opportunity to carry out their proposed experiments together with scientists from CERN and DESY.</p> <p>Beamline for Schools, an international competition open to high-school students from across the world, invites submission of proposals for an experiment that uses a beamline. Beamlines deliver a stream of subatomic particles to any given set-up, making it possible to study a broad variety of properties and processes in various scientific disciplines. They are operated at laboratories such as CERN and DESY. Due to the second Long Shutdown of CERN’s accelerators for maintenance and upgrade, there is currently no beam at CERN, which has opened up opportunities for partnerships with laboratories such as DESY during this period.</p> <p>"DESY is very pleased to welcome the BL4S competition for the second time," says Helmut Dosch, Chairman of the DESY Board of Directors. "The preparations must have been even more challenging for the students this year, but the high number of participants proves how popular this competition is. We are looking forward to meeting the next generation of scientists in autumn.”</p> <p>Since Beamline for Schools was launched in 2014, more than 11,000 students from 91 countries have participated. This year, 198 teams from 49 countries worldwide submitted a proposal for the competition’s seventh edition. From the entries received, 23 teams from 17 different countries (Argentina, Australia, Bulgaria, Canada, Chile, China, Germany, Japan, Netherlands, Philippines, Poland, Portugal, Spain, Switzerland, Turkey, United Kingdom, United Sates) were shortlisted. Each shortlisted team will receive BL4S t-shirts and a Cosmic Pi detector. Ten teams from Australia, Brazil, India, Italy, Japan, Mexico, Russia, Turkey, United States, were selected for Special Mention and will also receive BL4S t-shirts.</p> <p>“We look forward to welcoming this year’s winners to DESY. With the difficult situation worldwide, we are particularly grateful for and overwhelmed by the record number of entries. Students across the globe organised themselves via videoconferences and teamed up even across countries – an undoubtedly extraordinary and experience-rich situation for everyone,” said Sarah Aretz, BL4S project manager.</p> <p>The two winning teams of 2020 have proposed two very different experiments. This illustrates the wide spectrum of research questions that are possible within the boundary conditions of BL4S. The team Nations' Flying Foxes from Switzerland wants to detect a particle known as Δ+ Baryon. When high energy electrons interact with protons, these protons can be converted into the Δ+ particle. As the particle has a very short lifetime, the team will have to look for indirect signatures pretty much in the same way as short-lived particles are detected in the large experiments at CERN and DESY.</p> <p>“From the first brainstorming session for ideas two years ago, to finally going to DESY in a few months – this has been an amazing journey. What an incredible moment! This will truly shape our academic careers well into the future,” said Mikhail Slepovskiy from the Nations’ Flying Foxes team.</p> <p>The team ChDR Cheese from Germany wants to use a physics effect known as Cherenkov Diffraction Radiation (ChDR) as the basis of an innovative technology for the diagnosis of particle beams in accelerators. When particles move along certain materials such as fused silica, photons can be created while the particle beam itself is not disturbed. The properties of these photons, however, provide information about the beam that is valuable for the accelerator control system.</p> <p>“Hearing that we had won baffled all of us. It was like a dream come true. We are tremendously grateful to DESY and CERN for giving us this incredible opportunity and cheering us up in such trying times,” said Tobias Baumgartner from the ChDR Cheese team.</p> <p>Beamline for Schools is an Education and Outreach project funded by the <a href="https://cernandsocietyfoundation.cern/">CERN &amp; Society Foundation</a> and supported by individual donors, foundations and companies. For 2020, the competition is partly supported by the Wilhelm and Else Heraeus Foundation with additional contributions from the Arconic Foundation as well as from the Ernest Solvay Fund, managed by the King Baudouin Foundation.</p> <p><strong>Further information:</strong></p> <ul><li>BL4S website: <a href="http://beamline-for-schools.web.cern.ch">http://beamline-for-schools.web.cern.ch</a></li> <li>2020 edition: <a href="https://beamlineforschools.cern/editions/2020-edition">https://beamlinefor schools.cern/ editions/2020-edition</a></li> <li>Shortlisted and special mention teams 2020: <a href="https://beamlineforschools.cern/bl4s-shortlisted-and-special-mention-teams-2020">https://beamlineforschools.cern/bl4s-shortlisted-and-special-mention-teams-2020</a></li> <li>Previous winners: <a href="https://beamlineforschools.cern/bl4s-competition/winners">https://beamline forschools. cern/bl4s-competition/winners</a></li> </ul><p><strong>About CERN</strong></p> <p>CERN, the European Organization for Nuclear Research, is one of the world's leading laboratories for particle physics. The Organization is located on the French-Swiss border, with its headquarters in Geneva. Its Member States are: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Cyprus and Slovenia are Associate Member States in the pre-stage to Membership. Croatia, India, Lithuania, Pakistan, Turkey and Ukraine are Associate Member States. The European Union, Japan, JINR, the Russian Federation, UNESCO and the United States of America currently have Observer status.</p> <p><strong>About the CERN &amp; Society Foundation:</strong></p> <p>The CERN &amp; Society Foundation is a charitable foundation established by CERN to fund a programme of projects. These projects, in the areas of education and outreach, innovation and knowledge exchange, and culture and creativity, are inspired or enabled by CERN, but lie outside of its specific research mandate. The Foundation seeks the support of individuals, trusts, international organizations and commercial entities to help make these projects happen, and spread the CERN spirit of scientific curiosity for the inspiration and benefit of society.</p> <p><strong>About DESY</strong></p> <p>DESY is one of the world’s leading particle accelerator centres. Researchers use the large‐scale facilities at DESY to explore the microcosm in all its variety – ranging from the interaction of tiny elementary particles to the behaviour of innovative nanomaterials, the vital processes that take place between biomolecules and the great mysteries of the universe. The accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. DESY is a member of the Helmholtz Association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).</p> </div> Mon, 15 Jun 2020 08:33:38 +0000 mailys 155039 at https://home.cern Search for new physics through multiboson production https://home.cern/news/news/physics/search-new-physics-through-multiboson-production <span>Search for new physics through multiboson production</span> <span><span lang="" about="/user/147" typeof="schema:Person" property="schema:name" datatype="">cagrigor</span></span> <span>Wed, 06/10/2020 - 12:21</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2720394" data-filename="CMSATLAS" id="CERN-HOMEWEB-PHO-2020-065-2"> <a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-065-2" title="View on CDS"> <img alt="Search for new physics through multiboson production" src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-065-2/file?size=medium"/> </a> <figcaption> <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><strong><em>This media update is part of a series related to the <a href="http://www.lhcp2020.fr/">2020 Large Hadron Collider Physics conference</a>, taking place from 25 to 30 May 2020. Originally planned to take place in Paris, the conference is being held entirely online due to the COVID-19 pandemic.</em></strong></p> <hr /><p>At the LHCP conference this year, the <a href="https://atlas.cern/updates/atlas-news/new-results-lhcp-2020">ATLAS</a> and <a href="https://cms.cern/tags/physics-briefing">CMS</a> collaborations presented new results relating to a physics process called vector boson scattering. CMS also reported the first observation of the so-called “massive triboson production”. Studying these processes to test the Standard Model is important as it could shed light on new physics.</p> <p>During proton collisions at the LHC, many particles, including the carriers of the electroweak force – photons and W and Z bosons – are produced. These bosons are often referred to simply as vector bosons, in the Standard Model, and one of the processes that leads to their pair production is called vector boson scattering.</p> <p>Vector boson processes are an excellent probe to seek deviation from theoretical predictions. Two rare processes that are of particular interest as they probe the self-interactions of four vector bosons are diboson production via vector boson scattering and triboson production. The observation and measurement of these processes are important as they test the electroweak symmetry breaking mechanism, whereby the unified electroweak force separates into electromagnetic and weak forces in the Standard Model, and are complementary to the measurements of Higgs boson production and decay.</p> <p>In a vector boson scattering process, a vector boson is radiated from a quark in each proton and these vector bosons scatter off one another to produce a diboson final state. Triboson production refers instead to the production of three massive vector bosons.</p> <p>At the LHCP conference, physicists from the ATLAS and CMS collaborations presented new searches for the production of a pair of Z bosons via electroweak production including the vector boson scattering mechanism. <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-19/">ATLAS observed this process at 5.5 sigma</a> and <a href="http://cms-results.web.cern.ch/cms-results/public-results/preliminary-results/SMP-20-001/index.html">CMS reported strong evidence</a>. CMS also reported the first observation of a <a href="http://cms-results.web.cern.ch/cms-results/public-results/preliminary-results/SMP-19-008/index.html">W boson produced in association with a photon through the vector boson scattering process</a>, as well as more <a href="http://cms-results.web.cern.ch/cms-results/public-results/publications/SMP-19-012/index.html">precise measurements of the same-sign WW production, and an observation of the vector boson scattering production of a W and a Z boson</a>, complementing earlier <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-23/">ATLAS observations</a>.</p> <p>Another way to probe four-boson interaction is to study the very rare production of three massive bosons or tribosons. This April, the CMS experiment released a <a href="http://cms-results.web.cern.ch/cms-results/public-results/preliminary-results/SMP-19-014/index.html">5.7 sigma result of the triboson phenomenon</a>, establishing it as a firm observation, following <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-22/">the first evidence of this process seen by the ATLAS experiment last year</a>.</p> <p>Most physics processes of fundamental particles involve two or more individual particles that interact with each other via an intermediary particle that is emitted or absorbed in the process.</p> <p>“The more bosons produced, the rarer the event. This new observation of tribosons was very difficult because it is a much rarer process than the one that led to the Higgs boson discovery, and very interesting because it may reveal signs of new particles and anomalous interactions,” says Roberto Carlin, CMS spokesperson.</p> <p>In the triboson and vector boson scattering processes, W and Z can interact with themselves to create more W and Z particles, producing two or three bosons. W and Z being highly unstable particles, they quickly decay into leptons (electrons, muons, taus and their corresponding neutrinos) or quarks. But such processes are extremely rare and the diboson and triboson events that physicists look for are mimicked by background processes, making them even more difficult for physicists to analyse.</p> <p>“To separate signal from background, physicists have to be ingenious and employ advanced machine learning algorithms. This is a challenging task for such rare processes, and requires meticulous and thorough studies,” says Karl Jakobs, ATLAS spokesperson.</p> <p>The measurements of vector boson scattering and triboson production presented at LHCP 2020 are consistent with the predictions made by the Standard Model, which remains our best understanding of fundamental particles and their interactions. The above observations also provide physicists with tools to probe quartic self-interaction between massive electroweak bosons. The current measurements place constraints on the strength at which these quartic interactions take place and increased precision from the use of new datasets could open up horizons for new physics at higher energy scales in the LHC and lead to possible discoveries of new particles.</p> </div> Wed, 10 Jun 2020 10:21:41 +0000 cagrigor 155022 at https://home.cern Allen initiative – supported by CERN openlab – key to LHCb trigger upgrade https://home.cern/news/news/computing/allen-initiative-supported-cern-openlab-key-lhcb-trigger-upgrade <span>Allen initiative – supported by CERN openlab – key to LHCb trigger upgrade</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Andrew Purcell</div> </div> <span><span lang="" about="/user/34" typeof="schema:Person" property="schema:name" datatype="">achintya</span></span> <span>Tue, 06/09/2020 - 17:22</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2315673" data-filename="2018Start1" id="OPEN-PHO-EXP-2018-005-1"> <a href="//cds.cern.ch/images/OPEN-PHO-EXP-2018-005-1" title="View on CDS"> <img alt="Event collected at the beginning of 2018 data taking" src="//cds.cern.ch/images/OPEN-PHO-EXP-2018-005-1/file?size=medium"/> </a> <figcaption> Event collected at the beginning of 2018 data taking <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Last week, the LHC Experiments Committee formally accepted a proposal for a new first stage of the high-level trigger (HLT) for <a href="/science/experiments/lhcb">LHCb</a>. LHCb is one of the four main experiments on <a href="/science/accelerators/large-hadron-collider">the Large Hadron Collider (LHC)</a>. It is exploring what happened after the Big Bang that allowed matter to survive and build the Universe we see today.</p> <p>Like the other experiments on the LHC, LHCb uses a ‘trigger’ system to filter the huge amount of data produced by particle-collision events within its detectors. About 1 in 500 collision events are selected for further analysis. This trigger system is split into two levels: HLT 1, which reduces the data rate from around 40Tbit/s to 1–2 Tbit/s, and HLT 2, which reduces this further to 80 Gbit/s. This is then sent to storage and analysed using <a href="/science/computing/worldwide-lhc-computing-grid">the Worldwide LHC Computing Grid (WLCG)</a>.</p> <p>Until now, both HLT 1 and HLT 2 have been carried out using a farm of traditional computer chips called CPUs, which stands for ‘central processing units’. The new system – set to go into production in 2021 – will see HLT 1 run instead on graphical processing units (GPUs). The highly parallelised structure of GPUs can make them more efficient than general-purpose CPUs for running algorithms that process large blocks of data in parallel.</p> <p>Researchers at LHCb have been exploring the potential of GPUs for their trigger systems since around 2013. Building on that foundational work, this new system is the specific result of intense investigations carried out over the last two years, through an initiative called Allen, which is named after the pioneering computer scientist <a href="https://amturing.acm.org/award_winners/allen_1012327.cfm">Frances Elizabeth Allen</a>. The three lead developers for the Allen team are, Dorothea vom Bruch, a postdoctoral researcher from the French Laboratory of Nuclear and High-Energy Physics (LPNHE); Daniel Cámpora, a postdoctoral researcher from the University of Maastricht and the Dutch National Institute for Subatomic Physics (Nikhef), who was a PhD student during most of Allen’s development, co-supervised between CERN and the University of Sevilla in Spain; and Roel Aaij, a software engineer at Nikhef, who also played a major role in the development and commissioning of LHCb’s Run 1 and 2 HLT systems.</p> <figure class="cds-image align-right" id="OPEN-PHO-CCC-2020-001-1"><a href="//cds.cern.ch/images/OPEN-PHO-CCC-2020-001-1" title="View on CDS"><img alt="Allen,trigger,GPU,Computers and Control Rooms" src="//cds.cern.ch/images/OPEN-PHO-CCC-2020-001-1/file?size=large" /></a> <figcaption>The lead developers of the Allen initiative<span> (Image: CERN)</span></figcaption></figure><p>The Allen team’s new system can process 40 Tbit/s, using around 500 NVIDIA Tensor Core GPUs. It matches – from a physics point of view – the reconstruction performance for charged particles achieved on traditional CPUs. It has also been shown that the Allen system will not be limited in terms of memory capacity or bandwidth. Plus, not only can it be used to perform reconstruction, but it can also take decisions about whether to keep or reject collision events.</p> <p>A diverse range of algorithms has been implemented efficiently on Allen. This demonstrates the potential for GPUs not only to be used as computational accelerators in high-energy physics, but also as complete and standalone data-processing solutions. Other LHC experiments are also investigating the potential of GPUs; the ALICE experiment already used them in production for their HLT in Run 2.</p> <p>“We knew that this was an interesting avenue to explore, but we were surprised it worked out so quickly,” says Vladimir Gligorov of LPNHE, who leads LHCb’s Real Time Analysis project. “Over the last two years, the LHCb HLT team made the CPU HLT almost ten times faster, so it could work as planned, which is itself a huge achievement, and then this blue-skies project paid off as well. Now we can have the best of both worlds.”</p> <p>The Allen initiative has received support through a <a href="https://openlab.cern/">CERN openlab</a> project with the Italian company <a href="https://openlab.cern/members/e4-computer-engineering">E4 Computer Engineering</a>, which deploys hardware from NVIDIA. <a href="https://openlab.cern/project/testbed-gpu-accelerated-applications">This project</a> provides a testbed for GPU-accelerated applications, with several use cases spread across various LHC experiments.</p> <p>“Through the CERN openlab project, the team was able to capitalise on E4 Computer Engineering’s expertise and strong links with NVIDIA,” explains Maria Girone, CERN openlab CTO. “This helped ensure the team was supplied with GPUs on which to run tests, and meant there was a good link with the NVIDIA engineers, who provided advice for helping to make the code run as efficiently as possible on the GPUs. This kind of interaction with industry plays an important role in accelerating innovation and helps us to solve the computing challenges posed by the LHC’s ambitious upgrade programme.”</p> <p>“CERN openlab has played an important role in bringing together various teams across the laboratory and the experiments who are exploring the potential of GPUs,” explains Gligorov. “Seeing that others were exploring this technology too helped give us the confidence to push forward with these investigations. We’re certainly glad we did, as they’ve really paid off.”</p> <hr /><p><em>This article originally appeared on the <a href="https://openlab.cern/allen-initiative-supported-cern-openlab-key-lhcb-trigger-upgrade">CERN openlab website</a>. Read more about the new HLT 1 system in <a class="bulletin" href="https://link.springer.com/article/10.1007%2Fs41781-020-00039-7">an article published on 30 April in the journal </a></em><a href="https://link.springer.com/article/10.1007%2Fs41781-020-00039-7">Computing and Software for Big Science</a><em>.</em></p> </div> Tue, 09 Jun 2020 15:22:58 +0000 achintya 155015 at https://home.cern CERN statement on diversity and inclusiveness https://home.cern/news/news/cern/cern-statement-diversity-and-inclusiveness <span>CERN statement on diversity and inclusiveness</span> <span><span lang="" about="/user/195" typeof="schema:Person" property="schema:name" datatype="">anrassat</span></span> <span>Sat, 06/06/2020 - 17:47</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The search for knowledge is an intrinsic human aspiration; it cuts across borders of political ideologies, race, gender and cultures, at all times. CERN was founded with a spirit of international collaboration and peace at its core. Hence, our community strives to carry out its scientific mission in a cooperative, respectful and inclusive manner. </p> <p>Scientists are also citizens and can be individually or collectively victims of discrimination. Discrimination has not been fully eliminated from STEM, and there is more to be done. CERN reaffirms its commitment to ensuring diversity and inclusiveness of its personnel and to supporting all efforts to confront discrimination in scientific research activities, internal and external to the Organization. </p> <p>CERN understands that individuals within the members of the personnel may wish to express their peaceful and respectful support for the efforts to eliminate discrimination – in all its forms – in research and beyond.  </p> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Sat, 06 Jun 2020 15:47:19 +0000 anrassat 154998 at https://home.cern Live from the accelerators on 8 June https://home.cern/news/news/physics/live-accelerators-8-june <span>Live from the accelerators on 8 June</span> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span>Fri, 06/05/2020 - 16:35</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Welcome to the <a href="https://home.cern/science/accelerators/accelerator-complex">largest accelerator complex</a> in the world, which propels tiny pieces of matter to speeds of up to 99% of the speed of light. Four sophisticated machines form a chain around 15 kilometres long, in which protons, one of the tiny particles that make up matter, travel more than 1.7 million kilometres before being injected into the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider</a> (LHC). The LHC accelerates them further before colliding them about 40 million times per second inside four large detectors.</p> <p>CERN’s accelerator complex has been shut down since December 2018 to allow <a href="https://home.cern/news/news/accelerators/lhc-report-another-run-over-and-ls2-has-just-begun">major upgrades to take place</a>. After several months of work, the accelerators will gradually be recommissioned. But before their doors are closed, CERN invites you to discover them during an event on Facebook and YouTube, which will be streamed live from the brand new Linac 4 linear accelerator. You will go on the same journey as the particles, accompanied by CERN scientists who will reveal the secrets of these high-performance machines.</p> <p>On 8 June, CERN will celebrate the third birthday of the <a href="https://alumni.cern/"><strong>CERN Alumni Network</strong></a>. This network of former CERN personnel now has more than 6200 members who share information, help each other out and act as ambassadors for the Laboratory’s values of excellence and cooperation. This birthday celebration will bring together recruiters and CERN-grown talent.</p> <h4>Live from the accelerators on <a href="https://www.facebook.com/cern/">Facebook</a> and <a href="https://www.youtube.com/user/CERNTV">YouTube</a><br /> Join us on 8 June<br /> 4.00 p.m. CET: follow the journey of CERN’s alumni<br /> 5.00 p.m. CET: follow the journey of CERN’s particles</h4> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Fri, 05 Jun 2020 14:35:24 +0000 cmenard 154988 at https://home.cern Exploring new ways to see the Higgs boson https://home.cern/news/news/physics/exploring-new-ways-see-higgs-boson <span>Exploring new ways to see the Higgs boson</span> <span><span lang="" about="/user/18835" typeof="schema:Person" property="schema:name" datatype="">mailys</span></span> <span>Tue, 06/02/2020 - 16:18</span> <div class="field field--name-field-p-news-display-listing-img field--type-image field--label-hidden field--item"> <img src="/sites/home.web.cern.ch/files/2020-06/LHCP-ATLAS-CMS-Higgs%20%281%29.png" width="1440" height="720" alt="Collision events recorded by ATLAS (left) and CMS (right), used in the search for rare Higgs boson transformations (Image: CERN)" typeof="foaf:Image" class="img-responsive" /> </div> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2719664" data-filename="LHCP-ATLAS-CMS-Higgs%20(1)" id="CERN-HOMEWEB-PHO-2020-063-1"> <a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-063-1" title="View on CDS"> <img alt="Collision events recorded by ATLAS (left) and CMS (right), used in the search for rare Higgs boson transformations" src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-063-1/file?size=medium"/> </a> <figcaption> Collision events recorded by ATLAS (left) and CMS (right), used in the search for rare Higgs boson transformations <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><strong><em>This media update is part of a series related to the <a href="http://www.lhcp2020.fr/">2020 Large Hadron Collider Physics conference</a>, taking place from 25 to 30 May 2020. Originally planned to take place in Paris, the conference is being held entirely online due to the COVID-19 pandemic.</em></strong></p> <hr /><p>The <a href="/science/experiments/atlas">ATLAS</a> and <a href="/science/experiments/cms">CMS</a> collaborations presented their latest results on new signatures for detecting the <a href="/science/physics/higgs-boson">Higgs boson</a> at CERN’s Large Hadron Collider. These include searches for rare transformations of the Higgs boson into a Z boson – which is a carrier of one of the fundamental forces of nature – and a second particle. Observing and studying transformations that are predicted to be rare helps advance our understanding of particle physics and could also point the way to new physics if observations differ from the predictions. The results also included searches for signs of Higgs transformations into “invisible” particles, which could shine light on potential dark-matter particles. The analyses involved nearly 140 inverse femtobarns of data, or around 10 million billion proton–proton collisions, recorded between 2015 and 2018.</p> <p>The ATLAS and CMS detectors can never see a Higgs boson directly: an ephemeral particle, it transforms (or “decays”) into lighter particles almost immediately after being produced in proton–proton collisions, and the lighter particles leave telltale signatures in the detectors. However, similar signatures may be produced by other Standard-Model processes. Scientists must therefore first identify the individual pieces that match this signature and then build up enough statistical evidence to confirm that the collisions had indeed produced Higgs bosons.</p> <p>When it was discovered in 2012, the Higgs boson was observed mainly in transformations into pairs of Z bosons and pairs of photons. These so-called “decay channels” have relatively clean signatures making them more easily detectable, and they have been observed at the LHC. Other transformations are predicted to occur only very rarely, or to have a less clear signature, and are therefore challenging to spot.</p> <p>At LHCP, ATLAS presented the latest results of their searches for one such rare process, in which a Higgs boson transforms into a Z boson and a photon (γ). The Z thus produced, itself being unstable, transforms into pairs of leptons, either electrons or muons, leaving a signature of two leptons and a photon in the detector. Given the low probability of observing a Higgs transformation to Zγ with the data volume analysed, ATLAS was able to rule out the possibility that more than 0.55% of Higgs bosons produced in the LHC would transform into Zγ. “With this analysis,” says Karl Jakobs, spokesperson of the ATLAS collaboration, “we can show that our experimental sensitivity for this signature has now reached close to the <a href="/science/physics/standard-model">Standard Model</a>’s prediction.” The extracted best value for the H→Zγ signal strength, defined as the ratio of the observed to the predicted Standard-Model signal yield, is found to be 2.0<sup>+1.0</sup><sub>−0.9</sub>.</p> <p>CMS presented the results of the first search for Higgs transformations also involving a Z boson but accompanied by a ρ (rho) or φ (phi) meson. The Z boson once again transforms into pairs of leptons, while the second particle transforms into pairs of pions (ππ) in the case of the ρ and into pairs of kaons (KK) in the case of the φ. “These transformations are extremely rare,” says Roberto Carlin, spokesperson of the CMS collaboration, “and are not expected to be observed at the LHC unless physics from beyond the Standard Model is involved.” The data analysed allowed CMS to rule out that more than approximately 1.9% of Higgs bosons could transform into Zρ and more than 0.6% could transform into Zφ. While these limits are much greater than the predictions from the Standard Model, they demonstrate the ability of the detectors to make inroads in the search for physics beyond the Standard Model.</p> <p>The so-called “dark sector” includes hypothetical particles that could make up dark matter, the mysterious element that accounts for more than five times the mass of ordinary matter in the universe. Scientists believe that the Higgs boson could hold clues as to the nature of dark-matter particles, as some extensions of the Standard Model propose that a Higgs boson could transform into dark-matter particles. These particles would not interact with the ATLAS and CMS detectors, meaning they remain “invisible” to them. This would allow them to escape direct detection and manifest as “missing energy” in the collision event. At LHCP, ATLAS presented their latest upper limit – of 13% – on the probability that a Higgs boson could transform into invisible particles known as weakly interacting massive particles, or WIMPs, while CMS presented results from a new search into Higgs transformations to four leptons via at least one intermediate “dark photon”, also presenting limits on the probability of such a transformation occurring at the LHC.</p> <p>The Higgs boson continues to prove invaluable in helping scientists test the Standard Model of particle physics and seek physics that may lie beyond. These are only some of the many results concerning the Higgs boson that were presented at LHCP. You can read more about them on the <a href="https://atlas.cern/updates/atlas-news/new-results-lhcp-2020">ATLAS</a> and <a href="https://cms.cern/news/cms-shows-new-results-lhcp2020-conference">CMS</a> websites.</p> <h2><strong>Technical note</strong></h2> <p>When data volumes are not high enough to claim a definite observation of a particular process, physicists can predict the limits that they expect to place on the process. In the case of Higgs transformations, these limits are based on the product of two terms: the rate at which a Higgs boson is produced in proton–proton collisions (production cross-section) and the rate at which it will undergo a particular transformation to lighter particles (branching fraction).</p> <p>ATLAS expected to place an upper limit of 1.7 times the Standard Model expectation for the process involving Higgs transformations to a Z boson and a photon (H→Zγ) if such a transformation were not present; the collaboration was able to place an upper limit of 3.6 times this value, approaching the sensitivity to the Standard Model’s predictions. The CMS searches were for a much rarer process, predicted by the Standard Model to occur only once in every million Higgs transformations, and the collaboration was able to set upper limits of about 1000 times the Standard Model expectations for the H→Zρ and H→Zφ processes.</p> <h2>Links to the papers and notes</h2> <ul><li>ATLAS search for H→Zγ: <a href="https://cds.cern.ch/record/2717799">https://cds.cern.ch/record/2717799</a></li> <li>CMS search for H→Zρ or H→Zϕ: <a href="https://cds.cern.ch/record/2718949">https://cds.cern.ch/record/2718949</a></li> <li>ATLAS search for “invisible” transformations of the Higgs boson: <a href="https://cds.cern.ch/record/2715447">https://cds.cern.ch/record/2715447</a></li> <li>CMS search for Higgs transformations involving a dark photon: <a href="https://cds.cern.ch/record/2718976">https://cds.cern.ch/record/2718976</a></li> </ul></div> Tue, 02 Jun 2020 14:18:09 +0000 mailys 154954 at https://home.cern Neutron stars show their cores https://home.cern/news/news/physics/neutron-stars-show-their-cores <span>Neutron stars show their cores</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Ana Lopes</div> </div> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span>Tue, 06/02/2020 - 09:43</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2719533" data-filename="n_star_layers_printsize" id="CERN-HOMEWEB-PHO-2020-062-1"> <a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-062-1" title="View on CDS"> <img alt="Artist’s impression of a neutron star’s interior. The deeper the layer, the denser it is." src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2020-062-1/file?size=medium"/> </a> <figcaption> Shows an illustration of neutron star. <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Dive into the interior of neutron stars and you’ll find, guess what, neutrons. But it’s not as simple as that. The deeper the dive, the fuzzier and denser the interior gets. There’s no shortage of theories as to what might make up the centre of these cosmic objects. One hypothesis is that it’s filled with free quarks, not confined inside neutrons. Another is that it’s made of hyperons, particles that contain at least one quark of the “strange” type. Another still is that it consists of an exotic state of matter called a kaon condensate.</p> <p>In a paper just published in the journal <a href="https://www.nature.com/articles/s41567-020-0914-9"><em>Nature Physics</em></a>, a quintet of researchers including Aleksi Kurkela from CERN’s Theory department provides evidence that massive neutron stars can contain cores filled with free quarks. Such quark matter resembles the dense state of free quarks and gluons that is thought to have existed shortly after the Big Bang and can be <a href="/science/physics/heavy-ions-and-quark-gluon-plasma">recreated at particle colliders</a> on Earth, such as the Large Hadron Collider.</p> <p>To reach this evidence, the researchers combined information from astronomical observations of neutron stars with theoretical calculations. While astronomical observations provide some information about the stars’ interior, they don’t reveal their exact make-up.</p> <p>The theoretical calculations involved describing the state of matter inside a neutron star from the crust all the way down to the centre. To do this, the researchers used so-called equations of state, which relate the pressure of a state of matter to the energy density – the amount of energy packed into a system or region of space per unit volume.</p> <p>The team then plugged two pieces of information from astronomical data into these calculations: the observation that neutron stars can have masses equivalent to two Suns; and the possible values of a property called tidal deformability for a neutron star with a mass of about 1.4 times that of the Sun. The tidal deformability describes the stiffness of a star in response to stresses caused by the gravitational pull of a companion star, and was previously derived from observations of gravitational waves (ripples in the fabric of spacetime) emitted by the merger of two neutron stars.</p> <p>From this combination of theory and data, the researchers find that the cores of neutron stars with a mass 1.4 times that of the Sun should be filled with neutrons. By contrast, more massive stars can contain large quark-matter cores. For example, a 2-solar-mass neutron star with a radius of about 12 km could have a quark-matter core with a radius of about 6.5 km – about half of the star’s radius.</p> <p>“Our analysis does not completely rule out the existence of massive stars with neutron cores but it demonstrates that quark-matter cores are not an exotic alternative,” says Kurkela. “We can’t wait to incorporate new neutron-star data into our analysis and see how they will affect this conclusion.”</p> </div> Tue, 02 Jun 2020 07:43:50 +0000 abelchio 154953 at https://home.cern Cosmic rays throw up surprises, again https://home.cern/news/news/physics/cosmic-rays-throw-surprises-again <span>Cosmic rays throw up surprises, again</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Ana Lopes</div> </div> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span>Fri, 05/29/2020 - 12:23</span> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">The AMS detector on the International Space Station (Image: NASA) </div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Ever since astronauts attached the 7.5 tonne <a href="https://ams02.space/">AMS detector</a> to the International Space Station in May 2011, the space-based magnetic spectrometer, which was assembled at CERN, has collected data on more than 150 billion cosmic rays – charged particles that travel through space with energies up to trillions of electron volts. It’s an impressive amount of data, which has provided a wealth of information about these cosmic particles, but remarkably, as the spokesperson of the AMS team Sam Ting has previously noted, <a href="/news/news/experiments/latest-results-ams-experiment">none of the AMS results were predicted</a>. In a paper just published in <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.211102"><em>Physical Review Letters</em></a>, the AMS team reports measurements of heavy primary cosmic rays that, again, are unexpected.</p> <p>Primary cosmic rays are produced in supernovae explosions in our galaxy, the Milky Way, and beyond. The most common are nuclei of hydrogen, that is, protons, but they can also take other forms, such as heavier nuclei and electrons or their antimatter counterparts. AMS and other experiments have previously measured the number, or more precisely the so-called flux, of several of these types of cosmic rays and how the flux varies with particle energy and rigidity – a measure of a charged particle’s momentum in a magnetic field. But until now there have been no measurements of how the fluxes of the heavy nuclei of neon, magnesium and silicon change with rigidity. Such measurements would help shed new light on the exact nature of primary cosmic rays and how they journey through space.</p> <p>In its latest paper, the AMS team describes flux measurements of these three cosmic nuclei in the rigidity range from 2.15 GV to 3.0 TV. These measurements are based on 1.8 million neon nuclei, 2.2 million magnesium nuclei and 1.6 million silicon nuclei, collected by AMS during its first 7 years of operation (19 May 2011 to 26 May 2018). The neon, magnesium and silicon fluxes display unexpectedly identical rigidity dependence above 86.5 GV, including an also unexpected deviation above 200 GV from the single-power-law dependence predicted by the conventional theory of cosmic-ray origin and propagation. What’s more, the observed rigidity dependence is surprisingly different from that of the lighter primary helium, carbon and oxygen cosmic rays, which has been previously measured by AMS.</p> <p>The cosmic-ray plot continues to thicken. The AMS researchers have seen deviations from expected cosmic-ray behaviour before, including a rigidity dependence of the primary helium, carbon and oxygen cosmic rays that is distinctly different from that of the secondary lithium, beryllium and boron cosmic rays; secondary cosmic rays are produced by interactions between the primary cosmic rays and the interstellar medium.</p> <p>“Historically, cosmic rays are classified into two distinct classes – primaries and secondaries. Our new data on heavy primary cosmic rays show that primary cosmic rays have at least two distinct classes.” says Ting. “This is totally unexpected based on our previous knowledge of cosmic rays.”</p> <p>The new and surprising data is likely to keep theorists busy rethinking and reworking current cosmic-ray models. “Our previous observations have already generated new developments in cosmic-ray models. The new observations will provide additional challenges for the new models,” says Ting. And if the data that the detector is currently taking and sending back to CERN for analysis – after a successful <a href="/news/news/experiments/new-life-ams">series of spacewalks</a> that has extended its lifetime – throws up more surprises, theorists are likely to become even busier.</p> <p>Watch the <a href="https://www.youtube.com/watch?v=ogjUtZeoHOo&amp;feature=youtu.be">video</a> below and relive the drama of the complex spacewalks that have extended the remaining lifetime of the AMS detector to match that of the International Space Station itself.</p> <figure><iframe allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" frameborder="0" height="315" src="https://www.youtube-nocookie.com/embed/ogjUtZeoHOo?rel=0" width="560"></iframe> <figcaption>Video: CERN</figcaption></figure><p>Read more about the spacewalks and the previous AMS results in this <a href="https://cerncourier.com/a/ams-detector-given-a-new-lease-of-life/"><em>CERN Courier</em> article</a>.</p> </div> Fri, 29 May 2020 10:23:08 +0000 abelchio 154933 at https://home.cern CERN collaborations present new results on particles with charm quarks https://home.cern/news/news/physics/cern-collaborations-present-new-results-particles-charm-quarks <span>CERN collaborations present new results on particles with charm quarks</span> <span><span lang="" about="/user/147" typeof="schema:Person" property="schema:name" datatype="">cagrigor</span></span> <span>Fri, 05/29/2020 - 11:39</span> <div class="field field--name-field-p-news-display-listing-img field--type-image field--label-hidden field--item"> <img src="/sites/home.web.cern.ch/files/2020-05/TETRAQUARK_1.jpg" width="1000" height="563" alt="illustration of loosely-bound tetraquarks" typeof="foaf:Image" class="img-responsive" /> </div> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">The Xc1(3872) hadron, which contains charm quarks, could be a pair of two-quark particles loosely bound together (Image: CERN)</div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><strong><em>This media update is part of a series related to the <a href="http://www.lhcp2020.fr/">2020 Large Hadron Collider Physics conference</a>, taking place from 25 to 30 May 2020. Originally planned to take place in Paris, the conference is being held entirely online due to the COVID-19 pandemic.</em></strong></p> <hr /><p>The ALICE, CMS and LHCb collaborations at CERN present new measurements that show how charmed particles – particles containing charm quarks – can serve as “messengers” of two forms of matter made up of quarks and gluons: hadrons, which make up most of the visible matter in the present-day universe; and the quark–gluon plasma, which is thought to have existed in the early universe and can be recreated in heavy-ion collisions at the Large Hadron Collider (LHC). By studying charmed particles, physicists can learn more about hadrons, in which quarks are bound by gluons, as well as the quark–gluon plasma, in which quarks and gluons are not confined within hadrons.</p> <p>The main results are:</p> <p>The LHCb team obtained the most precise yet measurements of two properties of a particle known as χ<sub>c1</sub>(3872), a hadron containing charm quarks. The particle was discovered in 2003 and it has remained unclear whether it is a two-quark hadron, a more exotic hadron such as a tetraquark – a system of four quarks tightly bound together – or a pair of two-quark particles weakly bound in a molecule-like structure. Pinning down the nature of this hadron could extend physicists’ understanding of how quarks bind into hadrons. “Our results are consistent with χ<sub>c1</sub>(3872) being a pair of two-quark particles loosely bound together, but it does not fully rule out the tetraquark hypothesis or other possibilities,” says LHCb spokesperson Giovanni Passaleva.</p> <p>The CMS collaboration observed for the first time the transformation, or “decay”, of another particle, called B<sup>0</sup><sub>s</sub>, into the same χ<sub>c1</sub>(3872) particle. The researchers compared this decay with the previously observed decay of the B<sup>+</sup> meson, which had led to the first detection of the χ<sub>c1</sub>(3872) in 2003. Both types of decay link the behaviour of this hadron to the up and strange quarks. “Measured differences in the decay rates are intriguing and could provide further insight into the nature of the χ<sub>c1</sub>(3872), which has not yet been fully established,” says CMS spokesperson Roberto Carlin.</p> <p>The ALICE collaboration measured the so-called elliptic flow of hadrons containing charm quarks, in heavy-ion collisions. The hadrons are created during collisions that also create a quark–gluon plasma. Hadrons containing heavy quarks, like the charm quark, are excellent “messengers” of the quark–gluon plasma, meaning they carry important information about it. “The pattern observed by ALICE indicates that the heavy charm quarks are dragged by the quark–gluon plasma’s expansion,” says ALICE spokesperson Luciano Musa.</p> <p>Looking forward, the LHC collaborations aim to make more precise measurements of these messengers of the quark world using data from the next LHC run, which will benefit from largely upgraded experiment set-ups.</p> <p><em>Read more below for a comprehensive description of these results.</em></p> <p><strong>Charm quark results related to hadrons</strong></p> <p>The LHCb and CMS collaborations describe results from their studies of a hadron known as χ<sub>c1</sub>(3872). The particle was discovered in 2003 by the Belle experiment in Japan but it has remained unclear whether it is a two-quark hadron, a more exotic hadron such as a tetraquark – a system of four quarks tightly bound together – or a pair of two-quark particles weakly bound in a molecule-like structure.</p> <p>Pinning down the nature of χ<sub>c1</sub>(3872) could extend physicists’ understanding of how quarks bind into hadrons. The new studies by the CMS and LHCb collaborations shed new light on – but do not yet fully reveal – the nature of this particle.</p> <p>Using sophisticated analysis techniques and two different datasets, the LHCb team obtained the most precise measurements yet of the particle’s mass and determined for the first time and with a significance of more than five standard deviations the particle’s “width”, a parameter that determines the particle’s lifetime.</p> <p>Until now researchers had only been able to obtain upper limits on the allowed values of this parameter. The LHCb researchers detected χ<sub>c1</sub>(3872) particles in their datasets using the classic “bump”-hunting technique of searching for an excess (the bump) of collision events over a smooth background. Each dataset led to a measurement of the mass and width, and the results from both datasets agree with each other.</p> <p>“Our results are not only the most precise yet, they also show that the mass of χ<sub>c1</sub>(3872) is remarkably close to the sum of the masses of the<em> </em>D<sup>0</sup> and D<sup>*0</sup> charmed mesons,” says LHCb spokesperson Giovanni Passaleva. “This is consistent with χ<sub>c1</sub>(3872) being a pair of two-quark particles loosely bound together, but it does not fully rule out the tetraquark hypothesis or other possibilities.”</p> <p>Meanwhile, analysing a large dataset recorded over the course of three years, the CMS collaboration observed for the first time the transformation, or “decay”, of the B<sup>0</sup><sub>s</sub> particle into the χ<sub>c1</sub>(3872) and a ϕ meson. This two-quark particle, B<sup>0</sup><sub>s</sub>, is a relative of the B<sup>+</sup> meson, in the decay of which the Belle experiment first detected χ<sub>c1</sub>(3872). Like the LHCb team, the CMS team detected χ<sub>c1</sub>(3872) using the bump technique.</p> <p>“Our result is particularly interesting because we found that the rate at which the B<sup>0</sup><sub>s</sub> decays to the hadron χ<sub>c1</sub>(3872) and the ϕ meson is similar to that of the B<sup>0</sup> into χ<sub>c1</sub>(3872) and an anti-K<sup>0</sup> meson, whereas it is about twice as low as that for the previously observed B<sup>+</sup> decay into χ<sub>c1</sub>(3872) and the K<sup>+</sup> meson,” says CMS spokesperson Roberto Carlin. “In these decays, different quarks, other than the bottom quark, play a role,” Carlin explains. “The fact that the decay rates do not follow an obvious pattern may shed light on the nature of χ<sub>c1</sub>(3872).”</p> <p><strong>Charm quark results related to the quark–gluon plasma</strong></p> <p>At the other end of the quark-binding spectrum, the ALICE collaboration measured the so-called elliptic flow of hadrons containing a charm quark, either bound to a light quark (forming a D meson) or to an anticharm (making a J/ψ meson) in heavy-ion collisions. Hadrons containing heavy quarks, charm or bottom, are excellent messengers of the quark–gluon plasma formed in these collisions. They are produced in the initial stages of the collisions, before the emergence of the plasma, and thus interact with the plasma constituents throughout its entire evolution, from its rapid expansion to its cooling and its eventual transformation into hadrons.</p> <p>When heavy nuclei do not collide head on, the plasma is elongated and its expansion leads to a dominant elliptical modulation of the hadrons’ momentum distribution, or flow. The ALICE team found that, at low momentum, the elliptic flow of D mesons is not as large as that of pions, which contain only light quarks, whereas the elliptic flow of J/ψ mesons is lower than both but distinctly observed.</p> <p>“This pattern indicates that the heavy charm quarks are dragged by the quark–gluon plasma’s expansion,” says ALICE spokesperson Luciano Musa, “but likely to a lesser extent than light quarks, and that both D and J/ψ mesons at low momentum are in part formed by the binding, or recombination, of flowing quarks.”</p> <figure class="cds-image" id="ALICE-EVENTDISPLAY-2018-004-1"><a href="//cds.cern.ch/images/ALICE-EVENTDISPLAY-2018-004-1" title="View on CDS"><img alt="" src="//cds.cern.ch/images/ALICE-EVENTDISPLAY-2018-004-1/file?size=medium" /></a> <figcaption>An illustration of heavy-ion collisions recorded by ALICE. The colored lines represent the reconstructed trajectories of charged particles produced from the collision (Image: CERN)</figcaption></figure><p>Another measurement performed by the ALICE team – of the flow of electrons originating from decays of B hadrons, containing a bottom quark – indicates that bottom quarks are also sensitive to the elongated shape of the quark–gluon plasma. Upsilon particles, which are made up of a bottom quark and its antiquark, as opposed to a charm and anticharm like the J/ψ, <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.192301">do not exhibit significant flow</a>, likely because of their much larger mass and the small number of bottom quarks available for recombination.</p> <p>____</p> <p>Read more on the CMS and LHCb websites:</p> <ul><li><a href="https://cms.cern/news/discreet-charm-x3872">https://cms.cern/news/discreet-charm-x3872</a></li> <li><a href="https://lhcb-public.web.cern.ch/Welcome.html#X(3872)2020">https://lhcb-public.web.cern.ch/ Welcome.html#X(3872)2020</a></li> </ul><p>Original papers:</p> <ul><li>ALICE: <a href="https://arxiv.org/abs/2005.11131">https://arxiv.org/abs/2005.11131</a></li> <li>ALICE: <a href="https://arxiv.org/abs/2005.11130">https://arxiv.org/abs/2005.11130</a></li> <li>ALICE: <a href="https://arxiv.org/abs/2005.14518">https://arxiv.org/abs/2005.14518</a></li> <li>CMS: <a href="https://arxiv.org/abs/2005.04764">https://arxiv.org/abs/2005.04764</a></li> <li>LHCb: <a href="https://arxiv.org/abs/2005.13422">https://arxiv.org/abs/2005.13422</a></li> <li>LHCb: <a href="https://arxiv.org/abs/2005.13419">https://arxiv.org/abs/2005.13419</a></li> </ul></div> Fri, 29 May 2020 09:39:51 +0000 cagrigor 154932 at https://home.cern Fresh antimatter study by ALICE collaboration will help with the search for dark matter https://home.cern/news/news/physics/fresh-antimatter-study-alice-collaboration-will-help-search-dark-matter <span>Fresh antimatter study by ALICE collaboration will help with the search for dark matter</span> <span><span lang="" about="/user/18835" typeof="schema:Person" property="schema:name" datatype="">mailys</span></span> <span>Thu, 05/28/2020 - 11:08</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2653650" data-filename="201901-004_01" id="CERN-PHOTO-201901-004-1"> <a href="//cds.cern.ch/images/CERN-PHOTO-201901-004-1" title="View on CDS"> <img alt="ALICE empty structure after modules removal, during LS2" src="//cds.cern.ch/images/CERN-PHOTO-201901-004-1/file?size=medium"/> </a> <figcaption> ALICE empty structure after modules removal <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><strong><em>This media update is part of a series related to the <a href="http://www.lhcp2020.fr/">2020 Large Hadron Collider Physics conference</a>, taking place from 25 to 30 May 2020. Originally planned to take place in Paris, the conference is being held entirely online due to the COVID-19 pandemic.</em></strong></p> <hr /><p>The <a href="/science/experiments/alice">ALICE collaboration</a> has presented new results on the production rates of antideuterons based on data collected at the highest collision energy delivered so far at the Large Hadron Collider. The antideuteron is composed of an antiproton and an antineutron. The new measurements are important because the presence of antideuterons in space is a promising indirect signature of <a href="/science/physics/dark-matter">dark matter</a> candidates. The results mark a step forward in the search for dark matter.</p> <p>Recent astrophysical and cosmological results point towards dark matter being the dominant form of matter in the universe, accounting for approximately 85% of all matter. The nature of dark matter remains a great mystery, and cracking its secrets would open a new door for physics.</p> <p>Detecting antideuterons in space could be an indirect signature of dark matter, since they could be produced during the annihilation or decay of neutralinos or sneutrinos, which are hypothetical dark matter particles.</p> <p>Various experiments are on the hunt for antideuterons in the Universe, including the <a href="/science/experiments/ams">AMS detector</a> on the International Space Station. However, before inferring the existence of dark matter from the detection of these nuclei, scientists must account for both their rates of production by other sources (namely, collisions between cosmic rays and nuclei in the interstellar medium) and the rates of their annihilation caused by encountering matter on their journey. In order to assert that the detected antideuteron is related to the presence of dark matter, the production and annihilation rates must be well understood.</p> <p>By colliding protons in the LHC, ALICE scientists mimicked antideuteron production through cosmic ray collisions, and could thus measure the production rate associated with this phenomenon. These measurements provide a fundamental basis for modelling antideuteron production processes in space. By comparing the amount of antideuterons detected with that of their matter counterparts (deuterons, which do not annihilate in the detector), they were able to determine, for the first time, the annihilation probability of low-energy antideuterons.</p> <p>These measurements will contribute to future antideuteron studies in the Earth’s vicinity, and help physicists determine whether they are signatures of the presence of dark matter particles, or if on the contrary they are manifestations of known phenomena.</p> <p>In the future, these types of studies at ALICE could be extended to heavier antinuclei. “The LHC and the ALICE experiment represent a unique facility to study antimatter nuclei,” says ALICE Spokesperson Luciano Musa. “This research will continue to provide a crucial reference for the interpretation of future astrophysical dark matter searches.”</p> <hr style="width:50%;" /><p>Further reading:</p> <ul><li>Measurement of the low-energy antideuteron inelastic cross section [PDF]: <a href="https://arxiv.org/pdf/2005.11122.pdf">arXiv:2005.11122</a></li> <li>(Anti-)Deuteron production in pp collisions at √s = 13 TeV [PDF]: <a href="https://arxiv.org/pdf/2003.03184.pdf">arXiv:2003.03184</a></li> </ul></div> Thu, 28 May 2020 09:08:00 +0000 mailys 154928 at https://home.cern ISOLDE scores a first with laser spectroscopy of short-lived radioactive molecules https://home.cern/news/news/physics/isolde-scores-first-laser-spectroscopy-short-lived-radioactive-molecules <span>ISOLDE scores a first with laser spectroscopy of short-lived radioactive molecules</span> <span><span lang="" about="/user/18835" typeof="schema:Person" property="schema:name" datatype="">mailys</span></span> <span>Tue, 05/26/2020 - 12:07</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2702887" data-filename="201911-394_03" id="CERN-PHOTO-201911-394-3"> <a href="//cds.cern.ch/images/CERN-PHOTO-201911-394-3" title="View on CDS"> <img alt="ISOLDE facility - various pictures" src="//cds.cern.ch/images/CERN-PHOTO-201911-394-3/file?size=medium"/> </a> <figcaption> ISOLDE facility - various pictures <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>An international team of experimentalists and theorists working at CERN’s nuclear-physics facility <a href="/science/experiments/isolde">ISOLDE</a> have succeeded in performing the first ever laser-spectroscopy measurements of a short-lived radioactive molecule, radium monofluoride. For physicists studying molecules, laser spectroscopy, in which laser light is shone on molecules to reveal their energy structure, is a staple tool in the toolbox. Until now, however, researchers hadn’t been able to use the technique to study short-lived radioactive molecules, which contain one or more unstable nuclei. Compared to atoms, such molecules offer a superior means to explore fundamental symmetries of nature and to search for new physics phenomena. The results, published today in the journal <a href="https://www.nature.com/articles/s41586-020-2299-4"><em>Nature</em></a>, represent a pivotal step towards using these molecules for fundamental physics research and beyond.</p> <p>“Our measurements demonstrate that radium monofluoride molecules can be chilled down to temperatures that would allow researchers to investigate them in extraordinary detail,” says principal investigator Ronald Garcia Ruiz. “Our results pave the way to high-precision studies of short-lived radioactive molecules, which offer a new and unique laboratory for research in fundamental physics and other fields.”</p> <p>Radium monofluoride molecules are particularly interesting because they contain radium, some isotopes of which have <a href="/news/news/physics/isolde-spots-another-pear-shaped-nucleus">nuclei shaped like a pear</a>, with more mass at one end than the other. These exotic pear shapes amplify processes that break fundamental symmetries of nature and could reveal new physics phenomena beyond the <a href="/science/physics/standard-model">Standard Model</a>.</p> <p>For example, processes that break time-reversal symmetry – that is, that vary if you swap forwards in time for backwards – would give particles an electric dipole moment. This can be thought of as a shift of the cloud of virtual particles that surround every elementary particle away from the centre of mass. The Standard Model predicts a non-zero but very small electric dipole moment, but theories beyond the Standard Model often predict larger values. Nuclear pear shapes would amplify a putative electric dipole moment and would thus offer a sensitive means to probe new phenomena beyond the Standard Model – one that would be complementary to searches for new physics at high-energy particle colliders such as the <a href="/science/accelerators/large-hadron-collider">Large Hadron Collider</a>.</p> <p>The current experiment builds on theoretical investigations of the energy structure of radium monofluoride. Based on these investigations it was predicted that the molecule is amenable to laser cooling, whereby lasers are used to cool down atoms or molecules for high-precision studies.<strong> </strong>“This laser-spectroscopy study of radium monofluoride at ISOLDE provides strong evidence that the molecules can indeed be laser cooled,” says ISOLDE spokesperson Gerda Neyens.</p> <p>Garcia Ruiz and colleagues used the following method to obtain their results. After producing radioactive radium isotopes by firing protons from the CERN’s <a href="/science/accelerators/proton-synchrotron-booster">Proton Synchrotron Booster</a> on a uranium carbide target, radium monofluoride ions were formed by surrounding the target with carbon tetrafluoride gas. The radium monofluoride ions were then sent through ISOLDE’s Collinear Resonance Ionisation Spectroscopy (CRIS) setup, where the ions were turned into neutral molecules that were subsequently subjected to a laser beam that boosted them to excited energy states at specific laser frequencies. A subset of these excited molecules was then ionised with a second laser beam and deflected onto a particle detector for analysis.</p> <p>By analysing the measured spectra of ionised excited molecules, the team was able to identify the low-lying energy levels of the molecules and some of the properties that demonstrate that the molecules can be laser cooled for future precision studies.</p> <p>“Our technique allowed the study of radium monofluoride molecules that have lifetimes as short as a few days and are produced at rates lower than one million molecules per second,” says Garcia Ruiz.</p> <p>In addition to their potential in exploring fundamental symmetries, molecules made of short-lived isotopes can be highly abundant in space, for example in supernova remnants or in the gas ejected from mergers of neutron stars.</p> <p>“We anticipate that the approach can also be employed to perform laser spectroscopy on other molecules, including those composed of isotopes with lifetimes of a few tens of milliseconds,” Garcia Ruiz adds. This will allow future studies of bespoke molecules, designed to amplify symmetry-violating properties.</p> <figure class="cds-video" id="CERN-VIDEO-2017-012-002"><div><iframe allowfullscreen="true" frameborder="0" height="450" src="//cds.cern.ch/video/CERN-VIDEO-2017-012-002?responsive=1" width="100%"></iframe></div> <figcaption>Video presenting ISOLDE, CERN’s nuclear-physics facility <span>(Video: CERN)</span></figcaption></figure></div> Tue, 26 May 2020 10:07:45 +0000 mailys 154893 at https://home.cern