Measurements of branching fractions, polarizations, and direct CP-violation asymmetries in B --> rho K* and B --> f0(980) K* decays

TL;DR

This paper reports measurements of branching fractions, polarization fractions, and CP asymmetries in specific B-meson decay modes involving rho, f0(980), and K* particles, using data from the BABAR experiment.

Contribution

It provides the first measurements of these decay modes' branching fractions, polarization states, and CP asymmetries, including setting upper limits where signals are not statistically significant.

Findings

Measured branching fractions for several B decay modes.

Determined polarization fractions for significant decay modes.

Measured CP asymmetries, consistent with no CP violation within uncertainties.

Abstract

We report searches for B-meson decays to the charmless final states rho K* and f0(980) K* with a sample of 232 million BBbar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We measure the following branching fractions in units of 10^{-6}: B (B+ --> rho0 K*+) = 3.6 +/- 1.7 +/- 0.8 (< 6.1), B (B+ --> rho+ K*0) = 9.6 +/- 1.7 +/- 1.5, B (B0 --> rho- K*+) = 5.4 +/- 3.6 +/- 1.6 (< 12.0), B (B0 --> rho0 K*0) = 5.6 +/- 0.9 +/- 1.3, B (B+ --> f0(980) K*+) = 5.2 +/- 1.2 +/- 0.5, and B (B0 --> f0(980) K*0) = 2.6 +/- 0.6 +/- 0.9 (< 4.3). The first error quoted is statistical, the second systematic, and the upper limits, in parentheses, are given at the 90% confidence level. For the statistically significant modes we also measure the fraction of longitudinal polarization and the charge asymmetry: f_L (B+ --> rho+ K*0) = 0.52 +/- 0.10 +/- 0.04, f_L (B0 --> rho0 K*0) = 0.57 +/- 0.09 +/- 0.08, A_CP (B+ --> rho+ K*0) = -0.01 +/- 0.16 +/- 0.02, A_CP (B0 --> rho0 K*0) = 0.09 +/- 0.19 +/- 0.02, A_CP (B+ --> f_0(980) K*+) = -0.34 +/- 0.21 +/- 0.03, and A_CP (B0 --> f_0(980) K*0) = -0.17 +/- 0.28 +/- 0.02.