The CP-violating weak phase φs of the B0s meson and the decay width difference ΔΓs of the B0s light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of B0s→J/ψφ(1020) →μ+μ−K+K− decays. The analysed data set corresponds to an integrated luminosity of 19.7 fb−1 collected in pp collisions at a centre-of-mass energy of 8 TeV. A total of 49200 reconstructed B0s decays are used to extract the values of φs and ΔΓs by performing a time-dependent and flavour-tagged angular analysis of the μ+μ−K+K− final state. The weak phase is measured to be φs=−0.075 ±0.097 (stat) ±0.031 (syst) rad, and the decay width difference is ΔΓs=0.095 ±0.013 (stat) ±0.007 (syst) ps−1.
- CP violation