The C P-violating weak phase φs and the decay width difference DELTA-LAMBDAs between the light and heavy B0s mass eigenstates are measured with the CMS detector at the LHC in a sample of 48 500 reconstructed B0s → J/ψ φ(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 Delta-Lambdas 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 Delta Lambdas = 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, Delta Lambdas = 0.1032 ± 0.0095 (stat) ±0.0048 (syst) ps−1, a significant improvement over the 8 TeV result.

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 96.4fb−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+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=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.

(2021). Measurement of the CP-violating phase ϕs in the Bs0→J/ψϕ(1020)→μ+μ−K+K− channel in proton-proton collisions at √s = 13 TeV [journal article - articolo]. In PHYSICS LETTERS. SECTION B. Retrieved from http://hdl.handle.net/10446/179306

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

Re, V.;Vai, I.;
2021-01-01

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 96.4fb−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+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=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.
articolo
2021
The C P-violating weak phase φs and the decay width difference DELTA-LAMBDAs between the light and heavy B0s mass eigenstates are measured with the CMS detector at the LHC in a sample of 48 500 reconstructed B0s → J/ψ φ(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 Delta-Lambdas 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 Delta Lambdas = 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, Delta Lambdas = 0.1032 ± 0.0095 (stat) ±0.0048 (syst) ps−1, a significant improvement over the 8 TeV result.
Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.; Frühwirth, R.; Jeitler, M.; Kram...espandi
(2021). Measurement of the CP-violating phase ϕs in the Bs0→J/ψϕ(1020)→μ+μ−K+K− channel in proton-proton collisions at √s = 13 TeV [journal article - articolo]. In PHYSICS LETTERS. SECTION B. Retrieved from http://hdl.handle.net/10446/179306
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