We present a measurement of the time-dependent CP-violating asymmetry in Bs0→J/ψϕ decays, using data collected with the LHCb detector at the LHC. The decay time distribution of Bs0→J/ψϕ is characterized by the decay widths ΓH and ΓL of the heavy and light mass eigenstates, respectively, of the Bs0-B̅ s0 system and by a CP-violating phase ϕs. In a sample of about 8500 Bs0→J/ψϕ events isolated from 0.37  fb-1 of pp collisions at √s=7  TeV, we measure ϕs=0.15±0.18(stat)±0.06(syst)  rad. We also find an average Bs0 decay width Γs≡(ΓL+ΓH)/2=0.657±0.009(stat)±0.008(syst)  ps-1 and a decay width difference ΔΓs≡ΓL-ΓH=0.123±0.029(stat)±0.011(syst)  ps-1. Our measurement is insensitive to the transformation (ϕs,ΔΓs)↦(π-ϕs,-ΔΓs).

Measurement of the CP-Violating Phase ϕ_{s} in the Decay B_{s}^{0}→J/ψϕ

CARDINALE, ROBERTA;FONTANELLI, FLAVIO;PATRIGNANI, CLAUDIA;PETROLINI, ALESSANDRO;SANNINO, MARIO;
2012-01-01

Abstract

We present a measurement of the time-dependent CP-violating asymmetry in Bs0→J/ψϕ decays, using data collected with the LHCb detector at the LHC. The decay time distribution of Bs0→J/ψϕ is characterized by the decay widths ΓH and ΓL of the heavy and light mass eigenstates, respectively, of the Bs0-B̅ s0 system and by a CP-violating phase ϕs. In a sample of about 8500 Bs0→J/ψϕ events isolated from 0.37  fb-1 of pp collisions at √s=7  TeV, we measure ϕs=0.15±0.18(stat)±0.06(syst)  rad. We also find an average Bs0 decay width Γs≡(ΓL+ΓH)/2=0.657±0.009(stat)±0.008(syst)  ps-1 and a decay width difference ΔΓs≡ΓL-ΓH=0.123±0.029(stat)±0.011(syst)  ps-1. Our measurement is insensitive to the transformation (ϕs,ΔΓs)↦(π-ϕs,-ΔΓs).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/379536
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