Observation of $B^{\pm} \to ψ(2S) π^{\pm}$ and search for direct CP-violation

Abstract

We report the first observation of $B^{\pm}\toψ(2S)π^{\pm}$, a Cabibbo- and color-suppressed decay. This analysis is based on $657\times10^{6}$ $B\overline B$ events collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider. The measured branching fraction is ($2.44 \pm 0.22 \pm 0.20$)$\times 10^{-5}$ and the charge asymmetry is $\mathcal{A}=0.022 \pm 0.085 \pm 0.016$. The ratio of the branching fractions $\mathcal {B}(B^{\pm} \to ψ(2S) π^{\pm})$$/ \mathcal {B}(B^{\pm} \to ψ(2S) K^{\pm})$ $ = (3.99 \pm 0.36\pm 0.17)%$ is also determined.

6 pages, 3 figures, submitted to PRD(RC)