CERN: News https://home.cern/ en ProtoDUNE’s argon filling underway https://home.cern/news/news/experiments/protodunes-argon-filling-underway <span>ProtoDUNE’s argon filling underway</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p style="margin-bottom:15px">CERN’s Neutrino Platform houses a prototype of the <a href="https://www.dunescience.org/">Deep Underground Neutrino Experiment (DUNE</a>) known as ProtoDUNE, which is designed to test and validate the technologies that will be applied to the construction of the DUNE experiment in the United States.</p> <p>Recently, ProtoDUNE has entered a pivotal stage: the filling of one of its two particle detectors with liquid argon. Filling such a detector takes almost two months, as the chamber is gigantic – almost the size of a three-storey building. ProtoDUNE’s second detector will be filled in the autumn.</p> <p>ProtoDUNE will use the proton beam from the Super Proton Synchrotron to test the detecting of charged particles. This argon-filled detector will be crucial to test the detector response for the next era of neutrino research. Liquid argon is used in DUNE due to its inert nature, which provides a clean environment for precise measurements. When a neutrino interacts with argon, it produces charged particles that ionise the atoms, allowing scientists to detect and study neutrino interactions. Additionally, liquid argon's density and high scintillation light yield enhance the detection of these interactions, making it an ideal medium for neutrino experiments.</p> <p>Interestingly, the interior of the partially filled detector now appears green instead of its usual golden colour. This is because when the regular LED light is reflected inside the metal cryostat, the light travels through the liquid argon and the wavelength of the photons is shifted, producing a visible green effect.</p> <p>The DUNE far detector, which will be roughly 20 times bigger than protoDUNE, is being built in the United States. DUNE will send a beam of neutrinos from <a href="https://fnal.gov/">Fermi National Accelerator Laboratory</a> (Fermilab) near Chicago, Illinois, over a distance of more than 1300 kilometres through the Earth to neutrino detectors located 1.5 km underground at the <a href="https://sanfordlab.org/">Sanford Underground Research Facility</a> (SURF) in Lead, South Dakota.</p> <p>Watch a short time-lapse video of protoDUNE being filled with liquid argon:</p> <p><iframe allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen="" frameborder="0" height="380" referrerpolicy="strict-origin-when-cross-origin" src="https://www.youtube-nocookie.com/embed/FweOvhKsqaM?si=ddomS4fbntOcrJt8" title="YouTube video player" width="560"></iframe></p> </div> <span><span lang="" about="/user/24416" typeof="schema:Person" property="schema:name" datatype="">ckrishna</span></span> <span><time datetime="2024-04-12T10:15:38+02:00" title="Friday, April 12, 2024 - 10:15">Fri, 04/12/2024 - 10:15</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/chetna-krishna" hreflang="en">Chetna Krishna</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-12T08:30:00Z">Fri, 04/12/2024 - 10:30</time> </div> </div> Fri, 12 Apr 2024 08:15:38 +0000 ckrishna 189788 at https://home.cern Searching for new asymmetry between matter and antimatter https://home.cern/news/news/physics/searching-new-asymmetry-between-matter-and-antimatter <span>Searching for new asymmetry between matter and antimatter</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><figure class="cds-image" id="CERN-PHOTO-201812-329-15"><a href="//cds.cern.ch/images/CERN-PHOTO-201812-329-15" title="View on CDS"><img alt="Detectors,LHCb,Experiment,Opening" src="//cds.cern.ch/images/CERN-PHOTO-201812-329-15/file?size=large" /></a><figcaption>The LHCb detector seen in 2018 during its opening<span> (Image: CERN)</span></figcaption></figure><p style="text-align:start; margin-bottom:11px">Once a particle of matter, always a particle of matter. Or not. Thanks to a quirk of quantum physics, four known particles made up of two different quarks – such as the electrically neutral D meson composed of a charm quark and an up antiquark – can spontaneously oscillate into their <a href="https://www.cern/science/physics/antimatter">antimatter</a> partners and vice versa.</p> <p>At a <a href="https://indico.cern.ch/event/1355805/attachments/2826902/4938616/D0WS_mixing&amp;CPV_Ribatti.pdf">seminar</a> held recently at CERN, the <a href="/science/experiments/lhcb">LHCb</a> collaboration at the <a href="/science/accelerators/large-hadron-collider">Large Hadron Collider</a> (LHC) presented the results of its latest search for matter–antimatter asymmetry in the oscillation of the neutral D meson, which, if found, could help shed light on the mysterious matter–antimatter imbalance in the Universe.</p> <p>The weak force of the <a href="/science/physics/standard-model">Standard Model</a> of particle physics induces an asymmetry between matter and antimatter, known as CP violation, in particles containing quarks. However, these sources of CP violation are difficult to study and are insufficient to explain the matter–antimatter imbalance in the Universe, leading physicists to both search for new sources and to study the known ones better than ever before.</p> <p>In their latest endeavour, the LHCb researchers have rolled up their sleeves to measure with unprecedented precision a set of parameters that determine the matter–antimatter oscillation of the neutral D meson and enable the search for the hitherto unobserved but predicted CP violation in the oscillation.</p> <p>The collaboration had previously measured the same set of parameters, which are linked to the decay of the neutral D meson into a positively charged kaon and a negatively charged pion, using its full data set from Run 1 of the LHC and a partial data set from Run 2. This time around, the team analysed the full Run-2 data set and, by combining the result with that of its previous analysis, excluding the partial Run-2 data set, it obtained the most precise measurements of the parameters to date – the overall measurement uncertainty is 1.6 times smaller than the smallest uncertainty achieved before by LHCb.</p> <p>The results are consistent with previous studies, confirming the matter–antimatter oscillation of the neutral D meson and showing no evidence of CP violation in the oscillation. The findings call for future analyses of this and other decays of the neutral D meson using data from the <a href="/news/news/cern/third-run-large-hadron-collider-has-successfully-started">third run of the LHC</a> and its planned upgrade, the <a href="/science/accelerators/high-luminosity-lhc">High-Luminosity LHC</a>.</p> <p>Other neutral D meson decays of interest include the decay into a pair of two kaons or two pions, in which LHCb researchers <a href="https://arxiv.org/abs/1903.08726">observed</a> CP violation in particles containing charm quarks for the first time, and the decay into a neutral kaon and a pair of pions, with which LHCb <a href="https://arxiv.org/abs/2106.03744">clocked</a> the speed of the particle’s matter–antimatter oscillation. No avenue should be left unexplored in the search for clues to the matter–antimatter imbalance in the Universe and other cosmic mysteries.</p> <p><em>Find out more on the <a href="https://lhcb-outreach.web.cern.ch/2024/03/26/measurement-of-d0-%E2%88%92-d0-mixing-and-cp-violation-in-d0%E2%86%92k%CF%80-decays-2/">LHCb website</a>.</em></p> </div> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span><time datetime="2024-04-11T11:41:56+02:00" title="Thursday, April 11, 2024 - 11:41">Thu, 04/11/2024 - 11:41</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/ana-lopes" hreflang="en">Ana Lopes</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-11T15:00:00Z">Thu, 04/11/2024 - 17:00</time> </div> </div> Thu, 11 Apr 2024 09:41:56 +0000 abelchio 189781 at https://home.cern The next-generation triggers for CERN detectors https://home.cern/news/news/computing/next-generation-triggers-cern-detectors <span>The next-generation triggers for CERN detectors </span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p style="margin-bottom:11px">The experiments at the Large Hadron Collider (LHC) require high-performance event-selection systems – known as “triggers” in particle physics – to filter the flow of data to manageable levels. The triggers pick events with distinguishing characteristics, such as interactions or collisions of particles recorded in particle detectors, and make them available for physics analyses. In just a few seconds, the complex system can determine whether the information about a given collision event is worth keeping or not. </p> <p>The ATLAS and CMS experiments use triggers on two levels. The first trigger runs in sync with the rate of particle bunches colliding in the detectors, deciding in less than 10 microseconds which data to keep. Events that pass the first-level trigger move on to the second high-level trigger for further selection. The selected events are then sent to the <a href="https://home.cern/science/computing/data-centre">CERN Data Centre</a>, where the data is copied, stored and eventually made available to scientists around the world for data analysis.  </p> <p>In preparation for the <a href="https://home.cern/science/accelerators/high-luminosity-lhc">High-Luminosity LHC</a> (HL-LHC), the ATLAS and CMS detectors are being upgraded with finer spatial and timing granularity, which will result in more data for each collision. The principle is the same as taking a picture with a camera with more pixels: the resulting file will be bigger because the image contains more detail, and the picture will be of higher quality. To prepare for the data deluge expected when the LHC enters the high-luminosity era, scientists need to develop new strategies for more sophisticated event processing and selection.</p> <p>The key objective of the five-year Next-Generation Triggers (NextGen) project is to get more physics information out of the HL-LHC data. The hope is to uncover as-yet-unseen phenomena by more efficiently selecting interesting physics events while rejecting background noise. Scientists will make use of neural network optimisation, quantum-inspired algorithms, high-performance computing and field-programmable gate array (FPGA) techniques to improve the theoretical modelling and optimise their tools in the search for ultra-rare events.</p> <p>The foundations of the NextGen project were laid in 2022 when a group of private donors, including former Google CEO Eric Schmidt, visited CERN. This first inspiring visit eventually evolved into an agreement with the Eric and Wendy Schmidt Fund for Strategic Innovation, approved by the CERN Council in October 2023, to fund a project that would pave the way for the future trigger systems at the HL-LHC and beyond: NextGen was born.</p> <p>NextGen will collaborate with experts in academia and industry. The work builds on the open-science and knowledge-sharing principles embedded in CERN's institutional governance and modus operandi. The project includes a work package dedicated to education and outreach, a unique multi-disciplinary training programme for NextGen researchers and targeted events and conferences for the wider community of scientists interested in the field. The intellectual property generated as part of the NextGen Triggers project, owned by CERN, will be released and shared under open licences in compliance with the CERN Open Science Policy.</p> <p>The NextGen Triggers project will mark a new chapter in high-energy physics, leveraging upgraded event-selection systems and data-processing techniques to unlock a realm of discoveries.  </p> </div> <span><span lang="" about="/user/24416" typeof="schema:Person" property="schema:name" datatype="">ckrishna</span></span> <span><time datetime="2024-04-11T11:45:16+02:00" title="Thursday, April 11, 2024 - 11:45">Thu, 04/11/2024 - 11:45</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/antonella-del-rosso" hreflang="en">Antonella Del Rosso</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-11T10:00:00Z">Thu, 04/11/2024 - 12:00</time> </div> </div> Thu, 11 Apr 2024 09:45:16 +0000 ckrishna 189782 at https://home.cern ATLAS provides first measurement of the W-boson width at the LHC https://home.cern/news/news/physics/atlas-provides-first-measurement-w-boson-width-lhc <span>ATLAS provides first measurement of the W-boson width at the LHC</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><figure class="cds-image" id="ATLAS-PHOTO-2023-021-7"><a href="//cds.cern.ch/images/ATLAS-PHOTO-2023-021-7" title="View on CDS"><img alt="Proton Collisions,Event Displays,Physics,ATLAS" src="//cds.cern.ch/images/ATLAS-PHOTO-2023-021-7/file?size=large" /></a><figcaption>View of an ATLAS collision event in which a candidate W boson decays into a muon and a neutrino. The reconstructed tracks of the charged particles in the inner part of the ATLAS detector are shown as orange lines. The energy deposits in the detector’s calorimeters are shown as yellow boxes. The identified muon is shown as a red line. The missing transverse momentum associated with the neutrino is shown as a green dashed line. <span>(Image: ATLAS/CERN)</span></figcaption><p>The discovery of the <a href="/science/physics/higgs-boson">Higgs boson</a> in 2012 slotted in the final missing piece of the <a href="/science/physics/standard-model">Standard Model</a> puzzle. Yet, it left lingering questions. What lies beyond this framework? Where are the new phenomena that would solve the Universe's remaining mysteries, such as the nature of <a href="/science/physics/dark-matter">dark matter</a> and the origin of <a href="/science/physics/matter-antimatter-asymmetry-problem">matter–antimatter asymmetry</a>?</p> <p>One parameter that may hold clues about new physics phenomena is the “width” of the <a href="/science/physics/w-boson-sunshine-and-stardust">W boson</a>, the electrically charged carrier of the weak force. A particle’s width is directly related to its lifetime and describes how it decays to other particles. If the W boson decays in unexpected ways, such as into yet-to-be-discovered new particles, these would influence the measured width. As its value is precisely predicted by the Standard Model based on the strength of the charged weak force and the mass of the W boson (along with smaller quantum effects), any significant deviation from the prediction would indicate the presence of unaccounted phenomena.</p> <p>In a new <a href="https://arxiv.org/abs/2403.15085">study</a>, the <a href="/science/experiments/atlas">ATLAS</a> collaboration measured the W-boson width at the <a href="/science/accelerators/large-hadron-collider">Large Hadron Collider</a> (LHC) for the first time. The W-boson width had previously been measured at CERN’s <a href="/science/accelerators/large-electron-positron-collider">Large Electron–Positron (LEP) collider</a> and Fermilab’s <a href="http://www.fnal.gov/pub/tevatron/index.html">Tevatron</a> collider, yielding an average value of 2085 ± 42 million electronvolts (MeV), consistent with the Standard-Model prediction of 2088 ± 1 MeV. Using proton–proton collision data at an energy of 7 TeV collected during Run 1 of the LHC, ATLAS measured the W-boson width as 2202 ± 47 MeV. This is the most precise measurement to date made by a single experiment, and — while a bit larger — it is consistent with the Standard-Model prediction to within 2.5 standard deviations (see figure below).</p> <p>This remarkable result was achieved by performing a detailed particle-momentum analysis of decays of the W boson into an electron or a muon and their corresponding neutrino, which goes undetected but leaves a signature of missing energy in the collision event (see image above). This required physicists to precisely calibrate the ATLAS detector’s response to these particles in terms of efficiency, energy and momentum, taking contributions from background processes into account.</p> <p>However, achieving such high precision also requires the confluence of several high-precision results. For instance, an accurate understanding of W-boson production in proton–proton collisions was essential, and researchers relied on a combination of theoretical predictions validated by various measurements of <a href="https://atlas.cern/Updates/Briefing/WZ-properties-milestone">W and Z boson properties</a>. Also crucial to this measurement is the knowledge of the inner structure of the proton, which is described in parton distribution functions. ATLAS physicists incorporated and tested <a href="https://atlas.cern/updates/briefing/insight-proton-structure">parton distribution functions</a> derived by global research groups from fits to data from a wide range of particle physics experiments.</p> <p>The ATLAS collaboration measured the W-boson width simultaneously with the W-boson mass using a statistical method that allowed part of the parameters quantifying uncertainties to be directly constrained from the measured data, thus improving the measurement’s precision. The updated measurement of the W-boson mass is 80367 ± 16 MeV, which improves on and supersedes the previous ATLAS measurement using the same dataset. The measured values of both the mass and the width are consistent with the Standard-Model predictions.</p> <p>Future measurements of the W-boson width and mass using larger ATLAS datasets are expected to reduce the statistical and experimental uncertainties. Concurrently, advancements in theoretical predictions and a more refined understanding of parton distribution functions will help to reduce the theoretical uncertainties. As their measurements become ever more precise, physicists will be able to conduct yet more stringent tests of the Standard Model and probe for new particles and forces.</p> </figure><figure role="group"><img alt="Shows W-boson width measurements" data-entity-type="file" data-entity-uuid="4e019713-fdcd-4c27-869d-d839a90bfae0" height="auto" src="/sites/default/files/inline-images/abelchio/fig_15a.png" width="1980" loading="lazy" /><figcaption>Comparison of the measured W-boson width with the Standard-Model prediction and with measurements from the LEP and Tevatron colliders. The vertical grey band illustrates the Standard-Model prediction, while the black dots and the associated horizontal bands represent the published experimental results. (Image: ATLAS/CERN)</figcaption></figure></div> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span><time datetime="2024-04-10T12:03:51+02:00" title="Wednesday, April 10, 2024 - 12:03">Wed, 04/10/2024 - 12:03</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/atlas-collaboration" hreflang="en">ATLAS collaboration</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-10T09:57:48Z">Wed, 04/10/2024 - 11:57</time> </div> </div> Wed, 10 Apr 2024 10:03:51 +0000 abelchio 189778 at https://home.cern Computer Security: Swipes vs PINs vs passwords vs you https://home.cern/news/news/computing/computer-security-swipes-vs-pins-vs-passwords-vs-you <span>Computer Security: Swipes vs PINs vs passwords vs you</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p style="text-align:justify; margin-bottom:11px">What kind of person are you? An artist, like a painter? A credit card fanatic or just “in numbers”? Cerebral, a memoriser or even a genius? An influencer, like a peacock, or just prettily self-confident? A security buff or sufficiently security aware? Or just ignorant about security and your privacy? Let’s assume for a moment that the way you unlock your smartphone tells us which.</p> <p>There are many different ways to unlock your smartphone: swiping patterns, PIN numbers, passwords, biometric fingerprints or face recognition. Some are more secure, some less so. But all are better than nothing. So, let’s look at some of them.</p> <p><strong>Swiping patterns:</strong> The obvious choice on Android phones. Your favourite pattern on a 3x3 matrix. But as it should be a continuous swipe, the number of actual possibilities are quite limited, <a href="https://www.ieee-security.org/TC/SP2017/papers/226.pdf">boiling down to about 20 most-used swipes</a>. If yours is listed there, it may be time to move to another, more secure swipe. In any case, your swiping can be spied on and then tried once your smartphone is stolen.</p> <p>Worse ─ although it’s probably still academic ─ a small basic sonar system combining a local loudspeaker to emit acoustic signals inaudible to humans and a microphone to record them coming back again allowed researchers to use “<a href="https://arxiv.org/pdf/1808.10250.pdf">the echo signal […] to profile user interaction with the device</a>”, i.e. the way your finger swipes over and interacts with the screen. They’ve shown how this sonar can be employed to help identify the swipe pattern to unlock an Android phone – reducing the number of trials to be performed by an attacker by 70%. And that’s only their proof of concept… Maybe PINs and passwords are better?</p> <p><strong>PINs vs passwords:</strong> A common paradigm of computer security is linked to password complexity. Four-digit PIN numbers are no longer state of the art. And even six digits are not necessarily sufficient. While guessing and brute-forcing is difficult, as your smartphone should have a lock-out procedure only allowing a small number of tries before introducing timeouts or even wiping your phone completely(!), PINs can be easily spied on and replayed once your smartphone has been stolen*. Or do you shield your screen as you type your smartphone PIN as you do for your credit card at an ATM? Of course, a better choice is a long and complex password or even passphrase (unless you use one of <a href="https://en.wikipedia.org/wiki/List_of_the_most_common_passwords">the top 10 most-used passwords</a>). Admittedly, typing such long and complex passwords can be tedious. Enter: biometrics.</p> <p><strong>Biometrics:</strong> Still our favourite – using your fingerprint sensor or a capture of your face to unlock your phone. Your smartphone (and laptop) manufacturers went to extreme lengths to ensure that your biometric signature cannot be tampered with by your fingerprint on a piece of tape, your face in a photo or your sleeping self. And they also ensured that your biometric information is properly and securely stored using a special-purpose hardware chip (TPM: “trusted platform module”). Still, fingerprint authentication in particular has been broken into in the past for <a href="https://www.kaspersky.com/blog/fingerprint-brute-force-android/48303/">Android</a> and <a href="https://ia.acs.org.au/article/2023/beware--windows-laptop-fingerprint-scanners-can-be-hacked.html">Windows devices</a>, making face recognition our favourite choice to protect access to your smartphone and all the personal (and professional!) data you store and access with it.</p> <p> </p> <p><em>*</em><em>Actually, Apple’s latest security patch also fixed some issues with this.</em></p> <p>______</p> <p><em>Do you want to learn more about computer security incidents and issues at CERN? Follow our <a href="(https:/cern.ch/security/reports/en/monthly_reports.shtml">Monthly Report</a>. For further information, questions or help, check <a href="https://cern.ch/Computer.Security">our website</a> or contact us at <a href="mailto:Computer.Security@cern.ch">Computer.Security@cern.ch</a>.</em></p> </div> <span><span lang="" about="/user/151" typeof="schema:Person" property="schema:name" datatype="">anschaef</span></span> <span><time datetime="2024-04-09T14:03:31+02:00" title="Tuesday, April 9, 2024 - 14:03">Tue, 04/09/2024 - 14:03</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/computer-security-team" hreflang="en">Computer Security team</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-09T12:01:20Z">Tue, 04/09/2024 - 14:01</time> </div> </div> Tue, 09 Apr 2024 12:03:31 +0000 anschaef 189762 at https://home.cern Large Hadron Collider reaches its first stable beams in 2024 https://home.cern/news/news/accelerators/large-hadron-collider-reaches-its-first-stable-beams-2024 <span>Large Hadron Collider reaches its first stable beams in 2024</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><figure role="group" class="align-center"><img alt="LHC page 1" data-entity-type="file" data-entity-uuid="8dfa226f-4565-43e6-8711-602044af663e" height="auto" src="/sites/default/files/inline-images/ndinmore/Screenshot%202024-04-05%20at%2018.29.05.png" width="1678" loading="lazy" /><figcaption>LHC Page 1 showing the first stable beams of 2024 (Image: CERN)</figcaption></figure><p>On Friday 5 April, at 6.25 p.m., the LHC Engineer-in-Charge at the CERN Control Centre (CCC) announced that stable beams were back in the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider</a>, marking the official start of the 2024 physics data-taking season. The third year of LHC Run 3 promises six months of 13.6 TeV proton collisions at an even higher luminosity than before, meaning more collisions for the experiments to take data from. This will be followed by a period of lead ion collisions in October.</p> <p>Before the LHC could restart, each accelerator in the CERN complex had to be prepared for another year of physics data taking. Beginning with <a href="https://home.cern/science/accelerators/linear-accelerator-4">Linac4</a>, which welcomed its first beam two months ago, each accelerator has gone through a phase of beam commissioning in which it is gradually set up and optimised to be able to control all aspects of the beam, from its energy and intensity to its size and stability. During this phase researchers also test the accelerator’s performance and address any issues before it is used for physics. Following Linac4, which contains the source of protons for the beam, each accelerator was commissioned in turn: the <a href="C:\Users\naomidinmore\Documents\Home.cern\2024\4.%20April\o%09https:\home.cern\science\accelerators\proton-synchrotron-booster">Proton Synchrotron Booster</a>, the <a href="https://home.cern/science/accelerators/proton-synchrotron">Proton Synchrotron</a>, the <a href="https://home.cern/science/accelerators/super-proton-synchrotron">Super Proton Synchrotron</a>, and finally the LHC from 8 March until 5 April. The whole complex is now ready for data taking.</p> <p>Back to the CCC. While stable beams are the goal, the CCC engineers must first take several steps to achieve them. First, they must inject the beams into the LHC from the previous accelerators in the chain. Then begins the ramp-up process, which involves increasing the beam energy up to the nominal energy of 6.8 TeV. The next step – shown as “flat top” on <a href="https://op-webtools.web.cern.ch/vistar/">LHC Page 1</a> – is where the energy in the beams is consistent, but they’re not quite ready yet. In order to achieve stable beams, the circulating beams must then be “squeezed” and adjusted using the LHC magnets. This involves making the beams narrower and more centred on their paths, and therefore more likely to produce a high number of collisions in the detectors. Only after the squeezing and adjustment has been completed can stable beams be declared and the experiments around the LHC begin their data taking.</p> <p>Watch a video explaining the process from first injection to stable beams:</p> <figure class="cds-video" id="CERN-VIDEO-2022-012-001"><div><iframe allowfullscreen="true" frameborder="0" height="450" src="//cds.cern.ch/video/CERN-VIDEO-2022-012-001" width="100%"></iframe></div> <figcaption>Delphine Jacquet and Georges Trad, both engineers in charge of the LHC, explain how the LHC beams work from the injections of protons to stable beams. <span> (Video: CERN)</span></figcaption></figure><table border="1" cellpadding="1" cellspacing="1" style="width: 756.px;"><tbody><tr><td style="width: 750px;"> <p><strong>Did you know?</strong></p> <p>Although the solar eclipse on 8 April will not affect the beams in the LHC, the gravitational pull of the moon, like the tides, changes the shape of the LHC because the machine is so big. Read more <a href="https://home.cern/news/news/accelerators/full-moon-pulls-lhc-its-protons">here</a>.</p> </td> </tr></tbody></table></div> <span><span lang="" about="/user/33989" typeof="schema:Person" property="schema:name" datatype="">ndinmore</span></span> <span><time datetime="2024-04-05T10:28:16+02:00" title="Friday, April 5, 2024 - 10:28">Fri, 04/05/2024 - 10:28</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/naomi-dinmore" hreflang="en">Naomi Dinmore</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-05T16:30:09Z">Fri, 04/05/2024 - 18:30</time> </div> </div> Fri, 05 Apr 2024 08:28:16 +0000 ndinmore 189743 at https://home.cern FASER measures high-energy neutrino interaction strength https://home.cern/news/news/physics/faser-measures-high-energy-neutrino-interaction-strength <span>FASER measures high-energy neutrino interaction strength</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Operating at CERN’s Large Hadron Collider (LHC) since 2022, the <a href="https://home.cern/science/experiments/faser">FASER</a> experiment is designed to search for extremely weakly interacting particles. Such particles are predicted by many theories beyond the Standard Model that are attempting to solve outstanding problems in physics such as the nature of dark matter and the matter-antimatter imbalance in the Universe. Another goal of the experiment is to study interactions of high-energy neutrinos produced in the LHC collisions, particles that are nearly impossible to detect in the four big LHC experiments. Last week, at the annual<a href="http://moriond.in2p3.fr/"> </a><a href="http://moriond.in2p3.fr/">Rencontres de Moriond</a> conference, the FASER collaboration presented a measurement of the interaction strength, or “cross section”, of electron neutrinos (ν<sub>e</sub>) and muon neutrinos (ν<sub>μ</sub>). This is the first time such a measurement has been made at a particle collider. Measurements of this kind can provide important insights across different aspects of physics, from understanding the production of “forward” particles in the LHC collisions and improving our understanding of the structure of the proton to interpreting measurements of high-energy neutrinos from astrophysical sources performed by neutrino-telescope experiments.</p> <p>FASER is located in a side tunnel of the LHC accelerator, 480 metres away from the ATLAS detector collision point. At that location, the LHC beam is already nearly 10 metres away, bending away on its circular 27-kilometre path. This is a unique location for studying weakly interacting particles produced in the LHC collisions. Charged particles produced in the collisions are deflected by the LHC magnets. Most neutral particles are stopped by the hundreds of metres of rock between FASER and ATLAS. Only very weakly interacting neutral particles like neutrinos are expected to continue straight on and reach the location where the detector is installed.</p> <p>The probability of a neutrino interacting with matter is very small, but not zero. The type of interaction that FASER is sensitive to is where a neutrino interacts with a proton or a neutron inside the detector. In this interaction, the neutrino transforms into a charged “lepton” of the same family – an electron in the case of an ν<sub>e</sub>, and a muon in the case of a ν<sub>μ</sub> – which is visible in the detector. If the energy of the neutrino is high, several other particles are also produced in the collision.</p> <p>The detector used to perform the measurement consists of 730 interleaved tungsten plates and photographic emulsion plates. The emulsion was exposed during the period from 26 July to 13 September 2022 and then chemically developed and analysed in search of charged particle tracks. Candidates for neutrino interactions were identified by looking for clusters of tracks that could be traced back to a single vertex. One of these tracks then had to be identified as a high-energy electron or muon.</p> <figure role="group"><img alt="2 event displays of candidates for electronic neutrino and muonic neutrino" data-entity-type="file" data-entity-uuid="2da668e1-59dc-4aa3-b090-f93ec8aa1a26" src="/sites/default/files/inline-images/cmenard/Faser-2-neutrino-events.jpg" width="762" height="260" loading="lazy" /><figcaption>Event displays identified by the FASER collaboration as candidates for an νe (left) and a νμ (right) interacting in the detector. Invisible here, the neutrinos arrive from the left and then interact to create multiple tracks spraying out to the right (coloured lines), one of which is identified as a charged lepton (labelled). (credit: FASER collaboration)</figcaption></figure><p>In total, four candidates for an ν<sub>e</sub> interaction and eight candidates for a ν<sub>μ</sub> interaction have been found. The four ν<sub>e</sub> candidates represent the first direct observation of electron neutrinos produced at a collider. The observations can be interpreted as measurements of neutrino interaction cross sections, yielding (1.2<sup>+0.9</sup><sub>−0.8</sub>) ×10<sup>−38</sup> cm2 GeV<sup>−1</sup> in the case of the ν<sub>e</sub> and (0.5 ± 0.2) × 10<sup>−38</sup> cm2 GeV−1 in the case of the ν<sub>μ</sub>. The energies of the neutrinos were found to be in a range between 500 and 1700 GeV. No measurement of the neutrino interaction cross section had previously been made at energies above 300 GeV in the case of the ν<sub>e</sub> and between 400 GeV and 6 TeV in the case of the ν<sub>μ</sub>.</p> <p>The results obtained by FASER are consistent with expectations and demonstrate the ability of FASER to make neutrino cross-section measurements at the LHC. With the full LHC Run 3 data, 200 times more neutrino events will be detected, allowing much more precise measurements.</p> <p>Read more in the FASER <a href="https://arxiv.org/abs/2403.12520">publication</a>.</p> </div> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span><time datetime="2024-04-04T14:46:29+02:00" title="Thursday, April 4, 2024 - 14:46">Thu, 04/04/2024 - 14:46</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/piotr-traczyk" hreflang="en">Piotr Traczyk</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-04T12:45:32Z">Thu, 04/04/2024 - 14:45</time> </div> </div> Thu, 04 Apr 2024 12:46:29 +0000 cmenard 189735 at https://home.cern The CMS experiment at CERN measures a key parameter of the Standard Model https://home.cern/news/news/physics/cms-experiment-cern-measures-key-parameter-standard-model <span>The CMS experiment at CERN measures a key parameter of the Standard Model</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Last week, at the annual <em><a href="http://moriond.in2p3.fr/">Rencontres de Moriond</a> </em>conference, the CMS collaboration presented a measurement of the effective leptonic electroweak mixing angle. The result is the most precise measurement performed at a hadron collider to date and is in good agreement with the prediction from the Standard Model.</p> <p>The Standard Model of Particle Physics is the most precise description to date of particles and their interactions. Precise measurements of its parameters, combined with precise theoretical calculations, yield spectacular predictive power that allows phenomena to be determined even before they are directly observed. In this way, the Model successfully constrained the masses of the W and Z bosons (discovered at CERN in 1983), of the top quark (discovered at Fermilab in 1995) and, most recently, of the Higgs boson (discovered at CERN in 2012). Once these particles had been discovered, these predictions became consistency checks for the Model, allowing physicists to explore the limits of the theory’s validity. At the same time, precision measurements of the properties of these particles are a powerful tool for searching for new phenomena beyond the Standard Model – so-called “new physics” - since new phenomena would manifest themselves as discrepancies between various measured and calculated quantities.</p> <p>The electroweak mixing angle is a key element of these consistency checks. It is a fundamental parameter of the Standard Model, determining how the unified electroweak interaction gave rise to the electromagnetic and weak interactions through a process known as electroweak symmetry breaking. At the same time, it mathematically ties together the masses of the W and Z bosons that transmit the weak interaction. So, measurements of the W, the Z or the mixing angle provide a good experimental cross-check of the Model.</p> <p>The two most precise measurements of the weak mixing angle were performed by experiments at the CERN LEP collider and by the SLD experiment at the Stanford Linear Accelerator Center (SLAC). The values disagree with each other, which had puzzled physicists for over a decade. The new result is in good agreement with the Standard Model prediction and is a step towards resolving the discrepancy between the latter and the LEP and SLD measurements.</p> <p>“This result shows that precision physics can be carried out at hadron colliders,” says Patricia McBride, CMS spokesperson. “The analysis had to handle the challenging environment of LHC Run 2, with an average of 35 simultaneous proton-proton collisions. This paves the way for more precision physics at the High-Luminosity LHC, where five times more proton pairs will be colliding simultaneously.”</p> <p>Precision tests of the Standard Model parameters are the legacy of electron-positron colliders, such as CERN’s LEP, which operated until the year 2000 in the tunnel that now houses the LHC. Electron-positron collisions provide a perfect clean environment for such high-precision measurements. Proton-proton collisions in the LHC are more challenging for this kind of studies, even though the ATLAS, CMS and LHCb experiments have already provided a plethora of new ultra-precise measurements. The challenge is mainly due to huge backgrounds from other physics processes than the one being studied and to the fact that protons, unlike electrons, are not elementary particles. For this new result, reaching a precision similar to that of an electron-positron collider seemed like an impossible task, but it has now been achieved.</p> <p>The measurement presented by CMS uses a sample of proton-proton collisions collected from 2016 to 2018 at a centre-of-mass energy of 13 TeV and corresponding to a total integrated luminosity of 137 fb<sup>−1</sup>, meaning about 11 000 million million collisions! </p> <p>The mixing angle is obtained through an analysis of angular distributions in collisions where pairs of electrons or muons are produced. This is the most precise measurement performed at a hadron collider to date, improving on previous measurements from ATLAS, CMS and LHCb.</p> <p>Read more:</p> <ul><li><a href="https://cds.cern.ch/record/2893842?ln=en">CMS Physics Analysis Summary</a></li> <li><a href="https://cms.cern/news/towards-new-precision-era-study-electroweak-interactions">CMS Physics Briefing</a></li> </ul></div> <span><span lang="" about="/user/31077" typeof="schema:Person" property="schema:name" datatype="">angerard</span></span> <span><time datetime="2024-04-03T11:01:04+02:00" title="Wednesday, April 3, 2024 - 11:01">Wed, 04/03/2024 - 11:01</time> </span> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-03T14:00:00Z">Wed, 04/03/2024 - 16:00</time> </div> </div> Wed, 03 Apr 2024 09:01:04 +0000 angerard 189726 at https://home.cern CERN and the Swiss Arts Council announce the artists selected for the sixth edition of Connect https://home.cern/news/news/cern/cern-and-swiss-arts-council-announce-artists-selected-sixth-edition-connect <span>CERN and the Swiss Arts Council announce the artists selected for the sixth edition of Connect</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p><a href="https://arts.cern/programme/connect">Connect</a> is an art residency programme launched by <a href="https://arts.cern/">Arts at CERN</a> and <a href="https://prohelvetia.ch/en/">Pro Helvetia</a> in 2021. Dedicated to Swiss-based artists working at the intersection of science and artistic research, this research-led residency invites them to come to CERN to explore ideas and develop new work.</p> <p>The selected duo is composed of Robin Meier Wiratunga and Vimala Pons. Meier Wiratunga is an artist and composer who seeks to understand how humans, insects and objects think. Collaborating closely with scientific researchers, Meier Wiratunga's work blends machine learning with insights from animal intelligence, creating constellation scores where musical patterns emerge as ‘thinking tools'. Vimala Pons is an actress who has worked in independent and auteur cinema.</p> <p>Meier Wiratunga and Pons will dedicate their residency at CERN to developing their proposal titled <em>Guided Meditations for the End of the Universe</em>. This project aims to delve into cosmological theories about the end of the Universe to transform them into meditative and embodied experiences. Employing an anthropological approach to engage with science, the artists intend to employ spoken voice recordings, electronic music, light environments and sonified data from particle events.</p> <p>Now in its sixth edition, Connect has become a pivotal platform for Swiss-based artists to expand their artistic practice in dialogue with the field of physics and science at CERN. This collaboration framework between Arts at CERN and Pro Helvetia will continue through the next year with an iteration in Chile and India, sustaining its mission to foster interactions and dialogue between artistic and scientific communities.</p> <p>“We find ourselves in a challenging yet exciting time, as we witness the emergence of a strong and vibrant infrastructure devoted to the integration of artistic activity within the sciences,” says Mónica Bello, Curator and Head of Arts at CERN. “This is a transformational and promising development that presents unprecedented opportunities for cultural innovation. Connect is evidence of these dynamics, and I am proud to see that our partnership with Pro Helvetia is advancing further, bringing in new residents with different perspectives and backgrounds and strengthening the confluence of art and science in Switzerland.”</p> <p>“This sixth edition of Connect continues to reaffirm the significance of the interface between art, science and technology. The quality and diversity of applications received illustrate the rich interdisciplinarity inherent in this dynamic field, and the extent to which it is part of current artistic practice. We are happy to foster dialogue and innovation at this remarkable intersection and are very pleased about the ongoing collaboration with Arts at CERN,” explains Philippe Bischof, Director of Pro Helvetia.</p> <p>The jury of Connect was formed by Mónica Bello, Curator and Head of Arts at CERN; Giulia Bini, Head of Program and Curator of “Enter the Hyper-Scientific” at EPFL Lausanne; and Federica Martini, Head of the CCC - Critical Curatorial Cybermedia Master at HEAD Genève.</p> </div> <span><span lang="" about="/user/31077" typeof="schema:Person" property="schema:name" datatype="">angerard</span></span> <span><time datetime="2024-04-02T16:09:16+02:00" title="Tuesday, April 2, 2024 - 16:09">Tue, 04/02/2024 - 16:09</time> </span> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-03T12:00:00Z">Wed, 04/03/2024 - 14:00</time> </div> </div> Tue, 02 Apr 2024 14:09:16 +0000 angerard 189716 at https://home.cern AMS’s second new life https://home.cern/news/news/experiments/amss-second-new-life <span>AMS’s second new life</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p style="margin-bottom:8px">In 2011, the <a href="https://home.cern/science/experiments/ams">Alpha Magnetic Spectrometer</a> (AMS) was installed on the International Space Station (ISS). Since then, it has recorded more than 200 billion cosmic ray events and, while most of their sources are known, a few signatures in the data could point to dark matter. The detector’s latest upgrade will enable scientists to investigate this further.</p> <p>AMS collects cosmic ray particles that reach Earth coming either directly from the Sun or from far-away sources such as stars ending in supernovae or black holes. Most of the cosmic rays that AMS detects are protons, but heavy nuclei like iron or silicon also reach the detector. However, one signature is particularly intriguing. AMS has detected an unusually high flux of positrons – the antimatter partners of electrons. Positrons and other antimatter particles are rare in the Universe and hence not expected to be seen in the observed data at the strength found by AMS. Their origin is not yet confirmed; they could come from pulsars (fast rotating remnants of stars that emit regular signals), a yet-unknown astrophysical source or dark matter. The observed positron flux fits very well with dark matter models. But in order to investigate this more accurately, the AMS collaboration is now working on refurbishing the detector.</p> <p>The main upgrade will be a new detector layer with a higher number of silicon strips that will increase the acceptance of recording infalling particles by 300%. “By 2030, AMS will extend the energy range of the positron flux and reduce the error by a factor of two compared with current data,” says AMS spokesperson Sam Ting (MIT). This will allow the detector to investigate the positron signature even further.</p> <p>A second important addition will be three new radiative surfaces. Because AMS is exposed to direct sunlight, it was painted white to reflect excess heat and remain at operational temperatures. After 13 years in the demanding conditions of space, the paint has degraded and, to compensate for this, the new radiators will keep AMS cool again.</p> <figure class="cds-image" id="CERN-PHOTO-202403-063-2"><a href="//cds.cern.ch/images/CERN-PHOTO-202403-063-2" title="View on CDS"><img alt="AMS,upgrade,spacewalk" src="//cds.cern.ch/images/CERN-PHOTO-202403-063-2/file?size=large" /></a> <figcaption>Astronauts training at NASA’s “Neutral Buoyancy Lab” on a full-scale ISS model submerged under water where they learn to mount the new AMS upgrade parts <span> (Image: Corrado Gargiulo/NASA)</span></figcaption></figure><p>Currently, all the parts of the new upgrade, including electronics and hardware, are being built as “validation” and “qualification” models. If they pass all the tests happening at CERN, INFN Perugia and IABG in Germany, the final flight model will go into production. Astronauts are already training with the prototypes in space-like environments on Earth. In 2026, when the upgrade is launched, the astronauts will mount the new detector parts onto AMS during spacewalks. “Everything is going very, very fast,” says chief engineer Corrado Gargiulo (CERN). “This is a requirement, otherwise we arrive too late at the ISS for the upgrade to make sense.” Indeed, the mission now has an end date. NASA has scheduled the deorbiting of the ISS for 2030 and, until then, AMS will have plenty of cosmic ray events to record to explore the positron signature.</p> <p><iframe allowfullscreen="" frameborder="0" height="360" scrolling="no" src="https://cds.cern.ch/images/CERN-PHOTO-202401-005/export?format=sspp&amp;ln=en&amp;captions=true" width="480"></iframe></p> <p style="margin-bottom:8px"><span style="color:#999999;">A mock-up detector for the next AMS upgrade, which will be installed during the next anticipated spacewalk for AMS.  Another part of the upgrade includes a large power distribution system (PDS) radiator to restore AMS’s optimal thermal performance. (<a href="https://cds.cern.ch/record/2886635?ln=en">Image</a>: Chetna Krishna/CERN)</span></p> </div> <span><span lang="" about="/user/24416" typeof="schema:Person" property="schema:name" datatype="">ckrishna</span></span> <span><time datetime="2024-03-26T13:40:37+01:00" title="Tuesday, March 26, 2024 - 13:40">Tue, 03/26/2024 - 13:40</time> </span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-above"> <div class="field--label"><b>Byline</b></div> <div class="field--items"> <div class="field--item"><a href="/authors/sanje-fenkart" hreflang="en">Sanje Fenkart</a></div> </div> </div> <div class="field field--name-field-p-news-display-pub-date field--type-datetime field--label-above"> <div class="field--label"><b>Publication Date</b></div> <div class="field--item"><time datetime="2024-04-02T08:00:00Z">Tue, 04/02/2024 - 10:00</time> </div> </div> Tue, 26 Mar 2024 12:40:37 +0000 ckrishna 189686 at https://home.cern