Measurement of the CP-violating phase ϕs from Bs0→J/ψπ+π− decays in 13 TeV pp collisions

Abstract

Decays of B0s and B0s mesons into J/ψ π+π− final states are studied in a data sample corresponding to 1.9 fb−1 of integrated luminosity collected with the LHCb detector in 13 TeV pp collisions. A time-dependent amplitude analysis is used to determine the final-state resonance contributions, the CP-violating phase φs = −0.057 ± 0.060 ± 0.011 rad, the decay-width difference between the heavier mass B0 s eigenstate and the B0 meson of −0.050 ± 0.004 ± 0.004 ps−1, and the CP-violating parameter |λ| = 1.01+0.08 −0.06 ± 0.03, where the first uncertainty is statistical and the second systematic. These results are combined with previous LHCb measurements in the same decay channel using 7 TeV and 8 TeV pp collisions obtaining φs = 0.002 ± 0.044 ± 0.012 rad, and |λ| = 0.949 ± 0.036 ± 0.019.