Observation of the Rare Decay of the η Meson to Four Muons


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Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J., Bergauer T., Chatterjee S., ...More

Physical Review Letters, vol.131, no.9, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 131 Issue: 9
  • Publication Date: 2023
  • Doi Number: 10.1103/physrevlett.131.091903
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, INSPEC, zbMATH, DIALNET
  • Yıldız Technical University Affiliated: Yes

Abstract

A search for the rare Formula Presented double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of Formula Presented. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the Formula Presented decay as normalization, the branching fraction Formula Presented is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.