A flavour-tagged time-dependent angular analysis of B0s → J/ψ (→ e+ e−) ϕ decays is presented where the J/ψ meson is reconstructed through its decay to an e+ e− pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb^−1. The CP-violating phase and lifetime parameters of the B0s system are measured to be ϕ_s = 0.00 ± 0.28 ± 0.07 rad, ΔΓ_s = 0.115 ± 0.045 ± 0.011 ps^−1 and Γ_s = 0.608 ± 0.018 ± 0.012 ps^−1, where the first uncertainty is statistical and the second systematic. This is the first time that CP-violating parameters are measured in the B0s → J/ψ ϕ decay with an e+ e− pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions.

First Measurement of the CP-Violating Phase in B0s → J/ψ (→ e+ e−) ϕ Decays

Capriotti, L.;
2021

Abstract

A flavour-tagged time-dependent angular analysis of B0s → J/ψ (→ e+ e−) ϕ decays is presented where the J/ψ meson is reconstructed through its decay to an e+ e− pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb^−1. The CP-violating phase and lifetime parameters of the B0s system are measured to be ϕ_s = 0.00 ± 0.28 ± 0.07 rad, ΔΓ_s = 0.115 ± 0.045 ± 0.011 ps^−1 and Γ_s = 0.608 ± 0.018 ± 0.012 ps^−1, where the first uncertainty is statistical and the second systematic. This is the first time that CP-violating parameters are measured in the B0s → J/ψ ϕ decay with an e+ e− pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3582714
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