Measurement of the CP-violating phase ϕs in the Bs0→J/ψϕ(1020)→μ+μK+K channel in proton-proton collisions at s=13TeV

The CMS collaboration

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Abstract

The CP -violating weak phase ϕs and the decay width difference ΔΓs between the light and heavy Bs0 mass eigenstates are measured with the CMS detector at the LHC in a sample of 48500 reconstructed Bs0→J/ψϕ(1020)→μ+μK+K events. The measurement is based on a data sample corresponding to an integrated luminosity of 96.4fb−1, collected in proton-proton collisions at s=13TeV in 2017–2018. To extract the values of ϕs and ΔΓs, a time-dependent and flavor-tagged angular analysis of the μ+μK+K final state is performed. The analysis employs a dedicated tagging trigger and a novel opposite-side muon flavor tagger based on machine learning techniques. The measurement yields ϕs=−11±50(stat)±10(syst)mrad and ΔΓs=0.114±0.014(stat)±0.007(syst)ps−1, in agreement with the standard model predictions. When combined with the previous CMS measurement at s=8TeV, the following values are obtained: ϕs=−21±44(stat)±10(syst)mrad, ΔΓs=0.1032±0.0095(stat)±0.0048(syst)ps−1, a significant improvement over the 8 TeV result.

Original languageEnglish
Article number136188
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume816
DOIs
Publication statusPublished - 10 May 2021

Keywords

  • B physics
  • CMS
  • Oscillations
  • Physics

OECD FOS+WOS

  • 1.03 PHYSICAL SCIENCES AND ASTRONOMY

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