Measurement of the time-dependent CP asymmetries in $B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0$

Abstract

The first measurement of decay-time-dependent CP asymmetries in the decay $B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0$ and an updated measurement of the ratio of branching fractions $\mathcal{B}(B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)/\mathcal{B}(B_d^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)$} are presented. The results are obtained using data corresponding to an integrated luminosity of 3.0 fb${}^{-1}$ of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The results on the CP asymmetries are $A_{\hat{I}”\hat{I}“}(B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)=0.49_{-0.65}^{+0.77}(stat)\pm 0.06(syst)$, $C_{\mathrm{dir}}(B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)=-0.28\pm 0.41(stat)\pm 0.08(syst)$ and $S_{\mathrm{mix}}(B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)=-0.08\pm 0.40(stat)\pm 0.08(syst)$. The ratio $\mathcal{B}(B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)/\mathcal{B}(B_d^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0)$ is measured to be $0.0431\pm 0.0017(stat)\pm 0.0012(syst)\pm 0.0025(f_s/f_d)$, where the last uncertainty is due to the knowledge of the $B_s^0$ and $B_d^0$ production fractions.

18+5 pages, 5 figures, matching published version