First evidence of direct CP violation in charmless two-body decays of Bs mesons

Abstract

Using a data sample corresponding to an integrated luminosity of 0.35 ${\mathrm{fb}}^{-1}$ collected by LHCb in 2011, we report the first evidence of CP violation in the decays of $B_s^0$ mesons to $K^{\pm }\ddot{I}{€}^{\mp }$ pairs, $A_{CP}(B_s^0\to K\ddot{I}€)=0.27\pm 0.08(\mathrm{stat})\pm 0.02(\mathrm{syst})$, with a significance of 3.3$\ddot{I}ƒ$. Furthermore, we report the first observation of CP violation in $B^0$ decays at a hadron collider, $A_{CP}(B^0\to K\ddot{I}€)=-0.088\pm 0.011(\mathrm{stat})\pm 0.008(\mathrm{syst})$, with a significance exceeding 6$\ddot{I}ƒ$.

8 pages, 2 figures, 2 tables; v2 with minor changes after journal review