First measurement of time-dependent CP violation in Bs -> K+K- decays

TL;DR

This paper reports the first measurement of time-dependent CP violation in Bs -> K+K- decays, using LHCb data, providing new insights into CP asymmetries in B meson decays.

Contribution

It presents the first measurement of CP-violating asymmetries in Bs -> K+K- decays, expanding understanding of CP violation in B meson systems.

Findings

Measured C_{KK} = 0.14 ± 0.11 ± 0.03 and S_{KK} = 0.30 ± 0.12 ± 0.04 for Bs -> K+K-

Determined C_{pipi} = -0.38 ± 0.15 ± 0.02 and S_{pipi} = -0.71 ± 0.13 ± 0.02 for B0 -> pi+pi-

Results are consistent with existing measurements and theoretical expectations.

Abstract

Direct and mixing-induced CP-violating asymmetries in Bs -> K+K- decays are measured for the first time using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0 fb^{-1}, collected with the LHCb detector at a centre-of-mass energy of 7 TeV. The results are C_{KK} = 0.14 \pm 0.11 \pm 0.03 and S_{KK} = 0.30 \pm 0.12 \pm 0.04, where the first uncertainties are statistical and the second systematic. The corresponding quantities are also determined for B0 -> pi+pi- decays to be C_{pipi} = -0.38 \pm 0.15 \pm 0.02 and S_{pipi} = -0.71 \pm 0.13 \pm 0.02, in good agreement with existing measurements.