Measurements of the Absolute Branching Fractions of $B^\pm \to K^\pm X_{c\bar c}$

TL;DR

This paper reports precise measurements of the absolute branching fractions of B meson decays into charmonium states and kaons, including the first measurement of B+ to X(3872)K+ decay, providing insights into the nature of X(3872).

Contribution

The study significantly improves the accuracy of branching fraction measurements for B to charmonium decays and provides the first measurement of B+ to X(3872)K+ branching fraction.

Findings

Evidence for B+→X(3872)K+ decay at 3σ level.

First measurement of B+→X(3872)K+ branching fraction.

Supports the molecular hypothesis for X(3872).

Abstract

A study of the two body decays $B^\pm\rightarrow X_{c\bar c}K^\pm$, where X$_{c\bar c}$ refers to one charmonium state, is reported by BaBar collaboration using a data sample of 424 fb$^{-1}$. The absolute determination of branching fractions for these decays are significantly improved compared to previous BaBaR measurements. Evidence is found for the decay $B^+\rightarrow X(3872)K^+$ at the $3\sigma$ level. The absolute branching fraction ${\cal B}(B^+\rightarrow X(3872)K^+) = (2.1\pm0.6({\rm stat})\pm0.3({\rm syst}))\times 10^{-4}$ is measured for the first time. It follows that ${\cal B}(X(3872)\rightarrow J/\psi\pi^+\pi^-)=(4.1\pm1.3)\%$, supporting the hypothesis of a molecular component for this resonance.