Observation of the decay $B_s^0 \to \overline{D}^0 K^+ K^-$

TL;DR

This paper reports the first observation of the decay $B_s^0 o ar{D}^0 K^+ K^-$ and provides precise measurements of its branching fraction relative to similar decays, based on LHCb data at 7 and 8 TeV.

Contribution

The paper presents the first observation of the $B_s^0 o ar{D}^0 K^+ K^-$ decay and offers the most precise measurement of the branching fraction for $B^0 o ar{D}^0 K^+ K^-$ to date.

Findings

First observation of $B_s^0 o ar{D}^0 K^+ K^-$ decay.

Branching fraction of $B^0 o ar{D}^0 K^+ K^-$ measured as (6.1 ± 0.4 ± 0.3 ± 0.3) × 10^{-5}.

Branching fraction of $B_s^0 o ar{D}^0 K^+ K^-$ measured as (5.7 ± 0.5 ± 0.4 ± 0.5) × 10^{-5}.

Abstract

The first observation of the $B_s^0 \to \overline{D}^0 K^+ K^-$ decay is reported, together with the most precise branching fraction measurement of the mode $B^0 \to \overline{D}^0 K^+ K^-$. The results are obtained from an analysis of $pp$ collision data corresponding to an integrated luminosity of $3.0~\textrm{fb}^{-1}$. The data were collected with the LHCb detector at centre-of-mass energies of $7$ and $8$ TeV. The branching fraction of the $B^0 \to \overline{D}^0 K^+ K^-$ decay is measured relative to that of the decay $B^0 \to \overline{D}^0 \pi^+ \pi^-$ to be $$\frac{\mathcal{B}(B^0 \to \overline{D}^0 K^+ K^-)}{\mathcal{B}(B^0 \to \overline{D}^0 \pi^+ \pi^-)} = (6.9 \pm 0.4 \pm 0.3)\%,$$ where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the $B_s^0 \to \overline{D}^0 K^+ K^-$ decay mode relative to that of the corresponding $B^0$ decay is $$\frac{\mathcal{B}(B_s^0 \to \overline{D}^0 K^+ K^-)}{\mathcal{B}(B^0 \to \overline{D}^0 K^+ K^-)} = (93.0 \pm 8.9 \pm 6.9)\%.$$ Using the known branching fraction of ${B^0 \to \overline{D}^0 \pi^+ \pi^-}$, the values of ${{\mathcal B}(B^0 \to \overline{D}^0 K^+ K^- )=(6.1 \pm 0.4 \pm 0.3 \pm 0.3) \times 10^{-5}}$, and ${{\cal B}(B_s^0 \to \overline{D}^0 K^+ K^-)=}$ $(5.7 \pm 0.5 \pm 0.4 \pm 0.5) \times 10^{-5}$ are obtained, where the third uncertainties arise from the branching fraction of the decay modes ${B^0 \to \overline{D}^0 \pi^+ \pi^-}$ and $B^0 \to \overline{D}^0 K^+ K^-$, respectively.