A Study of the Rare Decays $B^0\to D_s^{(*)+} \pi^-$ and $B^0\to D_s^{(*)-} K^+$

TL;DR

This paper presents evidence for specific rare B meson decays involving D_s mesons and measures their branching fractions, providing new insights into these decay processes and setting upper limits for unobserved modes.

Contribution

It reports the first evidence and measurements of the branching fractions for B^0 decays to D_s^{(*)+} pi^- and D_s^{(*)-} K^+ and establishes upper limits for related decay modes.

Findings

Evidence for B^0→D_s^{+} π^- and B^0→D_s^{-} K^+ decays.

Measured branching fraction for B^0→D_s^{+} π^- as 3.2 ± 0.9 (stat.) ± 1.0 (syst.).

Set upper limits for B^0→D_s^{*+} π^- and B^0→D_s^{*-} K^+ decays.

Abstract

We report evidence for the decays $B^0\to D_s^{+} \pi^-$ and $B^0\to D_s^{-} K^+$ and the results of a search for $B^0 \to D_s^{*+} \pi^-$ and $B^0\to D_s^{*-} K^+$ in a sample of 84 milion Y(4S) decays into $B\bar{B}$ pairs collected with the BaBar detector at the PEP II asymmetric-energy $e^{+}e^{-}$ storage ring. We measure the branching fraction Br($B^0 \to D_s^{+} \pi^-) = 3.2 \pm 0.9 ({\rm stat.})\pm 1.0 ({\rm syst.})$. and Br($B^0 \to D_s^{+} \pi^-) = 3.2 \pm 1.0 ({\rm stat.})\pm 1.0 ({\rm syst.})$. We also set 90% C.L. limits BR($B^0 \to D_s^{*+} \pi^-) < 4.1\times 10^{-5}$ at 90% C.L and BR($B^0 \to D_s^{*-} K^+)< 2.5\times 10^{-5}$ at 90% C.L.