Measurement of the CKM angle ${\hat{I}}^3$ in $B^{\pm }\to D{K}^{\ast }(892{)}^{\pm }$ decays

Abstract

Measurements of $CP$ observables and the CKM angle ${\hat{I}}^3$ are performed in $B^{\pm }\to D{K}^{\ast }(892{)}^{\pm }$ decays, where $D$ represents a superposition of $D^0$ and $\overline{D}{}^0$ states, using the LHCb dataset collected during Run 1 (2011-2012) and Run 2 (2015-2018). A study of this channel is presented with the $D$ meson reconstructed in two-body final states $K^{\pm }\ddot{I}{€}^{\mp }$, $K^{+}{K}^{-}$ and $\ddot{I}{€}^{+}\ddot{I}{€}^{-}$; four-body final states $K^{\pm }\ddot{I}{€}^{\mp }\ddot{I}{€}^{\pm }\ddot{I}{€}^{\mp }$ and $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$; and three-body final states $K_S^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and $K_S^0{K}^{+}{K}^{-}$. This analysis includes the first observation of the suppressed $B^{\pm }\to [\ddot{I}{€}^{\pm }{K}^{\mp }{]}_D{K}^{\ast \pm }$ and $B^{\pm }\to [\ddot{I}{€}^{\pm }{K}^{\mp }\ddot{I}{€}^{\pm }\ddot{I}{€}^{\mp }{]}_D{K}^{\ast \pm }$ decays. The combined result gives ${\hat{I}}^3=(63\pm 13{)}^{\circ }$.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/3180/ (LHCb public pages)