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.

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

Bruschini, D.;
2023

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.
2023
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
Branching fractions; High rate; Integrated luminosity; Muon trigger; Normalisation; Proton proton collisions; Rare decays; Standard deviation; Statistical significance; η Mesons
   Enswarm
   UK Research and Innovation
   Innovate UK
   752730

   Search for Higgs bosons decaying to charm quarks
   HIGCC
   European Commission
   Horizon 2020 Framework Programme
   724704

   International Training Network for Statistics in High Energy Physics and Society
   INSIGHTS
   European Commission
   Horizon 2020 Framework Programme
   765710

   Advanced Multi-Variate Analysis for New Physics Searches at the LHC
   AMVA4NewPhysics
   European Commission
   Horizon 2020 Framework Programme
   675440
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/154760
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