Four CO2 cooling plants and accumulators in the service cavern of CMS in May 2025. (Photo by Jérôme Daguin) During recent shutdown periods, CERN engineers and technicians — in collaboration with the ATLAS and CMS teams — began installing the…
Read moreOn 15 May 2025, CMS officially inaugurated its new control room at Point 5 in Cessy, France. The celebration brought together guests from CERN management and representatives of all LHC experiments to mark this significant upgrade to CMS’s…
Read moreThe foreseen increase in luminosity and pileup at the High-Luminosity Large Hadron Collider (HL-LHC) [1] will challenge both the detector hardware and the reconstruction software. With higher pile-up, calorimeter energy reconstruction depends even…
Read moreSome of the most intriguing developments in physics begin not with a discovery, but with an anomaly, subtle, persistent, and difficult to ignore. In 2019, CMS reported a mild excess of around three standard deviations in a search for heavy…
Read moreThe CMS collaboration is excited to announce the launch of its new monthly newsletter, "Le Point Cinq." This fresh communication channel will provide regular updates on CMS physics highlights, the progress of upgrade projects, and essential…
Read moreThe first measurement of the W boson mass (mw) performed by the CMS Collaboration was announced in September 2024. This result has been long-awaited—the first LHC measurement of mW, by the ATLAS Collaboration, was shown nearly 7 years ago. In the…
Read moreThe unification of the electromagnetic and weak-nuclear forces into an electroweak theory was one of the major breakthroughs of 20th century particle physics. In the 1960s, Steven Weinberg, Sheldon Glashow, and Abdus Salam proposed that these two…
Read moreIt has been more than ten years since the discovery of the first scalar particle at the electroweak scale. This particle was discovered at the LHC in 2012, and it was quickly found to be a scalar that is compatible with the Higgs boson predicted by…
Read moreEarlier this month, the Large Hadron Collider reached an unprecedented milestone of 100 inverse femtobarns – equivalent to 10 million billion collisions – delivered to the ATLAS and CMS experiments in 2024, with 28 days of proton-proton collisions…
Read moreOn April 5th, 2024, stable beams returned to the LHC, marking the official start of the 2024 physics data-taking season. The photo captures CMS' Run Coordination team in the newly upgraded CMS control center, ready to oversee the exciting season…
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