CERN Courier Mar/Apr 2020

A candidate Higgs decay (H → ZZ* → 4µ) recorded by ATLAS on 10 June 2012.
A candidate Higgs decay (H → ZZ* → 4µ) recorded by ATLAS on 10 June 2012. (Image: ATLAS/Daniel Dominguez/CERN)

Welcome to the digital edition of the March/April 2020 issue of CERN Courier.

This issue of the Courier looks at the monumental impact of the LHC’s first 10 years of physics at the high-energy frontier (p40), and hears from those who have been at the sharp end of the machine (p49) and the experiments (p33) during this period. The LHC’s story has a long way to go, and it has parallels with LIGO and its quest to detect gravitational waves. In 1987, when a planning group set up by the CERN Council recommended a high-luminosity proton–proton collider with a centre-of-mass energy of 13–15TeV, LIGO had just been founded as a Caltech/MIT project. Site construction for LIGO began in 1994, the year the LHC was approved, and, two decades later, these two infrastructures made history with the direct discoveries of the Higgs boson and gravitational waves. Now, with the high-luminosity LHC upgrade and an enhanced Advanced LIGO “Plus” under way, physicists are vying to build a Higgs factory and a third-generation gravitational-wave interferometer to exploit these epochal discoveries to the full. Plans for the former have been at the centre of discussions of the European strategy update, which is about to conclude, while, as we report on p53, two sites in Europe are bidding to host the Einstein Telescope (ET). Interferometers might be cheaper than colliders, but, as former LIGO director Barry Barish explains in our interview on p61, a project like the ET requires professional management, tough decisions and a healthy appetite for risk.

Also in this issue: MICE reports results on muon-ionisation cooling (p7); AMS emerges from repair (p9); protons treat heart arrhythmia (p11); particle physics turns green (p59); machine-learning talks (p70); news briefs (p15); meeting reports (p23); reviews (p67); and much more.

j CERN Courier Mar/Apr 2020