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Measurement of CP violation in B0→D+D− and B0s→D+sD−s decays
A time-dependent, flavour-tagged measurement of CP violation is performed with B0→D+D− and B0s→D+sD−s decays, using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 6 fb−1. In B0→D+D− decays the CP-violation parameters are measured to be
SD+D−CD+D−=−0.552±0.100(stat)±0.010(syst),=0.128±0.103(stat)±0.010(syst).
In B0s→D+sD−s decays the CP-violating parameter formulation in terms of ϕs and |λ| results in
ϕs|λD+sD−s|=−0.086±0.106(stat)±0.028(syst)rad,=1.145±0.126(stat)±0.031(syst).
These results represent the most precise single measurement of the CP-violation parameters in their respective channels. For the first time in a single measurement, CP symmetry is observed to be violated in B0→D+D− decays with a significance exceeding six standard deviations.