Measurement of CP violation in B°→ψ(→ℓ+ℓ−) K°s(→ π+π−) decays

Abstract

[Abstract] A measurement of time-dependent CP violation in the decays of B° and ¯B° mesons to the final states J/ψ(→ µ+µ−)K°s, ψ(2S)(→ µ+µ−)K°s and J/ψ(→ e+e−)K°s with K°s→ π+π− is presented. The data correspond to an integrated luminosity of 6fb¯¹ collected at a center-of-mass energy of √s = 13TeV with the LHCb detector. The CP-violation parameters are measured to be Sψk°s = 0.717 ±0.013(stat) ± 0.008(syst), Cψk°s = 0.008 ±0.012(stat) ± 0.003(syst). This measurement of Sψk°s represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed.