Measurement of $CP$ violation in $B^0\to D^{\ast \pm }{D}^{\mp }$ decays

Abstract

The decay-time-dependent $CP$ asymmetry in $B^0\to D^{\ast \pm }{D}^{\mp }$ decays is measured using a data set corresponding to an integrated luminosity of $9$fb${}^{-1}$ recorded by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The $CP$ parameters are measured as $S_{D^{\ast }D}=-0.861\pm 0.077\text{(stat)}\pm 0.019\text{(syst)},$ $\hat{I}”S_{D^{\ast }D}=0.019\pm 0.075\text{(stat)}\pm 0.012\text{(syst)},$ $C_{D^{\ast }D}=-0.059\pm 0.092\text{(stat)}\pm 0.020\text{(syst)},$ $\hat{I}”C_{D^{\ast }D}=-0.031\pm 0.092\text{(stat)}\pm 0.016\text{(syst)},$ ${\mathcal{A}}_{D^{\ast }D}=0.008\pm 0.014\text{(stat)}\pm 0.006\text{(syst)}.$ The analysis provides the most precise single measurement of $CP$ violation in this decay channel to date. All parameters are consistent with their current world average values.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-036.html