Measurement of the CKM angle $\gamma$ in $B^{\pm} \to D K^*(892)^{\pm}$ decays

TL;DR

This paper measures the CKM angle gamma using B+/- to D K* decays with various D meson final states, utilizing LHCb data, and reports the first observation of certain suppressed decay modes, resulting in gamma = 63 +/- 13 degrees.

Contribution

First measurement of gamma in B+/- to D K* decays with multiple D final states, including the first observation of suppressed decay modes.

Findings

Measured gamma as (63 +/- 13) degrees.

First observation of suppressed B+/- to D K* decays.

Utilized multiple D meson decay channels for analysis.

Abstract

Measurements of $CP$ observables and the CKM angle $\gamma$ are performed in $B^{\pm} \to D K^*(892)^{\pm}$ 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 $K^{\pm}\pi^{\mp}$, $K^+K^-$ and $\pi^+\pi^-$; four-body final states $K^{\pm}\pi^{\mp}\pi^{\pm}\pi^{\mp}$ and $\pi^+\pi^-\pi^+\pi^-$; and three-body final states $K^0_{S} \pi^+\pi^-$ and $K^0_{S} K^+ K^-$. This analysis includes the first observation of the suppressed $B^{\pm} \to [\pi^{\pm}K^{\mp}]_D K^{*\pm}$ and $B^{\pm} \to [\pi^{\pm}K^{\mp}\pi^{\pm}\pi^{\mp}]_D K^{*\pm}$ decays. The combined result gives $\gamma=(63\pm 13)^\circ$.