Measurements of the branching fractions and CP asymmetries of B+ to J/psi pi+ and B+ to psi(2S) pi+ decays

TL;DR

This paper measures the branching fractions and CP asymmetries of B+ decays to J/psi pi+ and psi(2S) pi+ using LHC data, finding results consistent with no CP violation.

Contribution

First precise measurements of these decay modes' branching fractions and CP asymmetries at 7 TeV proton-proton collisions.

Findings

Branching fraction B(B+ to J/psi pi+) = (3.88 +- 0.11 +- 0.15) x 10^{-5}

Branching fraction B(B+ to psi(2S) pi+) = (2.52 +- 0.26 +- 0.15) x 10^{-5}

No evidence of direct CP violation in these decays.

Abstract

A study of B+ to J/psi pi+ and B+ to psi(2S) pi+ decays is performed with data corresponding to 0.37 fb-1 of proton-proton collisions at sqrt(s)=7 TeV. Their branching fractions are found to be B(B+ to J/psi pi+) = (3.88 +- 0.11 +- 0.15) x 10^{-5} and B(B+ to psi(2S) pi+) = (2.52 +- 0.26 +- 0.15) x 10^{-5}, where the first uncertainty is related to the statistical size of the sample and the second quantifies systematic effects. The measured CP asymmetries in these modes are ACP(J/psi pi) = 0.005 +- 0.027 +- 0.011 and ACP(psi(2S) pi) = 0.048 +- 0.090 +- 0.011 with no evidence of direct CP violation seen.