From freyablekman@sciencemastodon.com on Mastodon: # CMSPaper 1216: The η (=eta) is a special particle.This paper finds a new way the η can decay: into four muons. This is important because it measures muon-photon interactions, and quite accurately at that. That is a precision test of theory predictions, including some inputs to the muonic magnetic dipole moment. These decays are very rare, and used specially designed new @ CMSexperiment triggers to collect this sample! http:// cms-results.web.cern.ch/cms-re sults/public-results/publications/BPH-22-003/index.html # science # particlephysics # cern # discovery # alttext