Observation of $B_s^0\to {\bar{D}}^0{K}_S^0$ and evidence for $B_s^0\to {\bar{D}}^{\ast 0}{K}_S^0$ decays

Abstract

The first observation of the $B_s^0\to {\bar{D}}^0{K}_S^0$ decay mode and evidence for the $B_s^0\to {\bar{D}}^{\ast 0}{K}_S^0$ decay mode are reported. The data sample corresponds to an integrated luminosity of 3.0 ${\text{fb}}^{-1}$ collected in $pp$ collisions by LHCb at center-of-mass energies of 7 and 8 TeV. The branching fractions are measured to be \begin{align*} \mathcal{B}(B^0_s\to\bar{D}^0 \bar{K}^0) &= (4.3\pm0.5(\text{stat})\pm0.3(\text{syst})\pm0.3(\text{frag})\pm0.6(\text{norm}))\times10^{-4},\\ \mathcal{B}(B^0_s\to\bar{D}^{*0} \bar{K}^0) &= (2.8\pm1.0(\text{stat})\pm0.3(\text{syst})\pm0.2(\text{frag})\pm0.4(\text{norm}))\times10^{-4}, \end{align*} where the uncertainties are due to contributions coming from statistical precision, systematic effects, and the precision of two external inputs, the ratio $f_s/f_d$ and the branching fraction of $B^0\to {\bar{D}}^0{K}_S^0$, which is used as a calibration channel.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-050.html