  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.
