Measurements of Branching Fraction, Polarization, and Direct-CP-Violating Charge Asymmetry in B+ --> K*0 Rho+ Decays

TL;DR

This paper reports the first observation of the B+ --> K*0 Rho+ decay, measuring its branching fraction, polarization, and charge asymmetry using data from the BABAR detector, providing insights into CP violation and decay dynamics.

Contribution

First observation of B+ --> K*0 Rho+ decay with measurements of branching fraction, polarization, and CP asymmetry, advancing understanding of vector-vector B decays.

Findings

Branching fraction measured as (17.0 +- 2.9 (stat) +- 2.0 (syst) +0.0 -1.9 (non-resonant)) x 10^-6

Longitudinal polarization fraction fL = 0.79 +- 0.08 (stat) +- 0.04 (syst) +- 0.02 (non-resonant)

Direct CP asymmetry A_CP = -0.14 +- 0.17 (stat) +- 0.04 (syst)

Abstract

With a sample of 88.8 BBbar pairs produced at PEP-II in e+e- annihilation through the Upsilon(4S) resonance and recorded with the BABAR detector, we search for the B+ --> K*0 Rho+ decay mode. A signal is observed for the first time with a significance of more than 5 sigma. We measure a preliminary branching fraction of BR(B+ --> K*0 Rho+)=[17.0 +-2.9 (stat) +-2.0 (syst) +0.0 -1.9 (non-resonant)] 10(-6). The "non-resonant" error corresponds to the uncertainty from non-resonant backgrounds not modeled in the fit. The measurement of the longitudinal-polarized component to this vector-vector penguin decay is of special interest. We measure fL= 0.79 +-0.08(stat) +-0.04 (syst) +- 0.02 (non-resonant). We measure the direct-CP-violating charge asymmetry in this mode to be A_CP = -0.14 +- 0.17 +- 0.04.