Observation of the $B^0\to {\overline{D}}^{\ast 0}{K}^{+}\ddot{I}{€}^{-}$ and $B_s^0\to {\overline{D}}^{\ast 0}{K}^{-}\ddot{I}{€}^{+}$ decays

Abstract

The first observations of $B^0\to {\overline{D}}^{\ast }(2007{)}^0{K}^{+}\ddot{I}{€}^{-}$ and $B_s^0\to {\overline{D}}^{\ast }(2007{)}^0{K}^{-}\ddot{I}{€}^{+}$ decays are presented, and their branching fractions relative to that of the $B^0\to {\overline{D}}^{\ast }(2007{)}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decay are reported. These modes can potentially be used to investigate the spectroscopy of charm and charm-strange resonances and to determine the angle ${\hat{I}}^3$ of the CKM unitarity triangle. It is also important to understand them as a source of potential background in determinations of ${\hat{I}}^3$ from $B^{+}\to D{K}^{+}$ and $B^0\to D{K}^{+}\ddot{I}{€}^{-}$ decays. The analysis is based on a sample corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ of proton--proton collision data at $13\mathrm{TeV}$ centre-of-mass energy recorded with the LHCb detector. The ${\overline{D}}^{\ast }(2007{)}^0$ mesons are fully reconstructed in the ${\overline{D}}^0\ddot{I}{€}^0$ and ${\overline{D}}^0{\hat{I}}^3$ channels, with the ${\overline{D}}^0\to K^{+}\ddot{I}{€}^{-}$ decay. A novel weighting method is used to subtract background while simultaneously applying an event-by-event efficiency correction to account for resonant structures in the decays.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-043.html (LHCb public pages)