Observation of $B^0_s \to K^{*\pm}K^\mp$ and evidence for $B^0_s \to K^{*-}\pi^+$ decays

TL;DR

This paper reports the first observation of the decay $B^0_s o K^{*\pm}K^\mp$ and evidence for $B^0_s o K^{*\pm}\pi^\mp$ decays, measuring their branching fractions using LHCb data at 7 TeV.

Contribution

The study provides the first measurements of these specific $B_s^0$ decay modes, expanding understanding of rare hadronic B meson decays.

Findings

First observation of $B^0_s o K^{*\pm}K^\mp$ decay.

Evidence for $B^0_s o K^{*\pm}\pi^\mp$ decay.

Measured branching fractions with statistical and systematic uncertainties.

Abstract

Measurements of the branching fractions of $B^0_s \to K^{*\pm}K^\mp$ and $B^0_s \to K^{*\pm}\pi^\mp$ decays are performed using a data sample corresponding to $1.0 \ {\rm fb}^{-1}$ of proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of $7\mathrm{\,TeV}$, where the $K^{*\pm}$ mesons are reconstructed in the $K^0_{\rm S}\pi^\pm$ final state. The first observation of the $B^0_s \to K^{*\pm}K^\mp$ decay and the first evidence for the $B^0_s \to K^{*-}\pi^+$ decay are reported with branching fractions \begin{eqnarray} {\cal B}(B^0_s \to K^{*\pm}K^\mp) & = & (12.7\pm1.9\pm1.9) \times 10^{-6}, \\ {\cal B}(B^0_s \to K^{*-}\pi^+) & = & ~(3.3\pm1.1\pm0.5) \times 10^{-6}, \end{eqnarray} where the first uncertainties are statistical and the second are systematic. In addition, an upper limit of ${\cal B}(B^0 \to K^{*\pm}K^\mp) < 0.4 \ (0.5) \times 10^{-6}$ is set at $90\,% \ (95\,%)$ confidence level.