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

TL;DR

This paper reports an improved measurement of the branching fraction and direct CP asymmetry for B+- --> rho+- pi0 decays using a large data sample from the BaBar experiment, providing more precise results and confirming previous findings.

Contribution

The study presents the most precise measurement to date of the B+- --> rho+- pi0 branching fraction and CP asymmetry, surpassing previous measurements with a larger data sample and advanced analysis techniques.

Findings

Branching fraction BR = (10.0 +- 1.4 (stat) +- 0.9 (syst)) x 10^-6

CP asymmetry Acp = -0.01 +- 0.13 (stat) +- 0.02 (syst)

Statistical significance of the branching fraction is 8.7 sigma

Abstract

An improved measurement of the process B+- --> rho+- pi0 is presented. The data sample of 211/fb comprises 232 million Y(4S) --> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy B Factory at SLAC. The yield and CP asymmetry are calculated using an extended maximum likelihood fitting method. The branching fraction and asymmetry are found to be BR(B+- --> rho+- pi0) = [10.0 +- 1.4 (stat) +- 0.9 (syst)]x 10^-6 and Acp(B+- --> rho+- pi0) = -0.01 +- 0.13 (stat) +- 0.02 (syst), superseding previous measurements. The statistical significance of the branching fraction is calculated to be 8.7sigma.