Physicists have glimpsed an elusive particle transition, one that helps to confirm the Standard Model of particle physics. The CMS (Compact Muon Spectrometer) experiment at the Large Hadron Collider in Switzerland announced Friday, July 19, 2013, that they had observed the β_s particle decaying into two muons. The rate of this decay turned out to be in very close agreement with predictions of the Standard Model. Greg Landsberg, professor of physics at Brown and physics coordinator of the CMS, played a leading role in overseeing the analysis, and Brown graduate student Zeynep Demiragli helped with the paper’s final plots. Recent Brown postdoctoral fellow Gena Kukartsev served on the CMS review committee overseeing the analysis. Brown professors Dave Cutts, Ulrich Heintz, and Meenakshi Narain, together with Landsberg, provide the leadership of the Brown group, an active component of the CMS Collaboration. While the new finding bolsters the Standard Model, there is still hope that the CMS experiment will turn up new physics. “The announcement today leaves open the possibility of new discoveries of beyond-the-Standard-Model physics with the CMS experiment,” Cutts said. “Anticipation is high within CMS for studies with the new data expected in 2015, when the LHC resumes operation at double the previous collision energy.”