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+μ−K+K− events. The measurement is based on a data sample corresponding to an integrated luminosity of 96.4 fb-1, collected in proton-proton collisions at √s=13 TeV in 2017–2018. To extract the values of ϕs and ΔΓs, a time-dependent and flavor-tagged angular analysis of the μ+μ−K+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=8 TeV , 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 language | English |
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Article number | 136188 |
Number of pages | 27 |
Journal | Physics Letters B |
Volume | 816 |
Early online date | 3 Mar 2021 |
DOIs | |
Publication status | Published - 10 May 2021 |
Bibliographical note
Publisher Copyright:© 2021 The Author(s)
Keywords
- B physics
- CMS
- Oscillations
- Physics