Measurements of branching fraction, polarization, and charge asymmetry of B+ --> rho+ rho0 and a search for B+ --> rho+ f0(980)

TL;DR

This paper reports measurements of the branching fraction, polarization, and charge asymmetry in B+ -> rho+ rho0 decays, and searches for B+ -> rho+ f0(980), providing new experimental data on these decay modes.

Contribution

It provides the first precise measurements of these decay parameters and sets an upper limit on the B+ -> rho+ f0(980) decay, advancing understanding of B meson decay dynamics.

Findings

Branching fraction B = (16.8 ± 2.2 ± 2.3) x 10^-6

Longitudinal polarization fraction f_L = 0.905 ± 0.042 +0.023-0.027

Charge asymmetry A_CP = -0.12 ± 0.13 ± 0.10

Abstract

We measure the branching fraction, polarization and CP asymmetry of B+ -> rho+rho0 decays and search for the decay B+ -> rho+f_0(980) based on a data sample of 231.8 million Y(4S)->BB decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. In B+ -> rho+rho0 decays we measure B=(16.8+-2.2+-2.3)x10-6, f_L=0.905+-0.042+0.023-0.027, and A_CP=-0.12+-0.13+-0.10, and find an upper limit on the branching fraction of B+ -> rho+f_0(980)(->pi+pi-) of 1.9x10-6 at 90% Confidence Level.