Measurement of the B+ --> rho+ pi0 Branching Fraction and Direct CP Asymmetry

TL;DR

This paper reports precise measurements of the branching fraction and direct CP asymmetry in B+ --> rho+ pi0 decays, using data from the BABAR detector, with results consistent with no CP violation.

Contribution

First measurement of the B+ --> rho+ pi0 branching fraction and CP asymmetry using a large data sample at BABAR.

Findings

Branching fraction: (10.2 +- 1.4(stat) +- 0.9(syst)) x 10^-6

CP asymmetry: -0.01 +- 0.13(stat) +- 0.02(syst)

Results are consistent with no direct CP violation.

Abstract

We present improved measurements of the branching fraction and CP asymmetry for the process B+ --> rho+ pi0. The data sample corresponding to 211/fb comprises 232 million Y(4S)-->BBbar decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The yield and CP asymmetry are measured using an extended maximum likelihood fitting method. The branching fraction and CP asymmetry are found to be BR(B+ --> rho+ pi0)= [10.2 +- 1.4(stat) +- 0.9(syst)] x 10^-6 and Acp (B+ --> rho+ pi0) = -0.01 +- 0.13(stat) +- 0.02(syst).