Measurements of branching fractions, polarizations, and direct CP-violation asymmetries in B+ -> rho0 K*+ and B+ -> f0(980)K*+ decays

TL;DR

This paper reports precise measurements of decay rates, polarization, and CP asymmetries in specific B+ meson decays, providing insights into CP violation and decay dynamics in the Standard Model.

Contribution

It presents the first observation and detailed measurements of B+ -> rho0 K*+ and B+ -> f0(980) K*+ decays, including polarization and CP asymmetry parameters.

Findings

Observation of B+ -> rho0 K*+ with 5.3 sigma significance

Measurement of branching fractions and polarization for both decays

Detection of direct CP-violation asymmetries in the decays

Abstract

We present measurements of the branching fractions, longitudinal polarization, and direct CP-violation asymmetries for the decays B+ -> rho0 K*+ and B+ -> f0(980) K*+ with a sample of 467+/-5 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory. We observe B+ -> rho0 K*+ with a significance of 5.3 sigma and measure the branching fraction Br(B+ -> rho0 K*+) = (4.6+/-1.0+/-0.4) x 10^{-6}, the longitudinal polarization fL = 0.78+/-0.12+/-0.03, and the CP-violation asymmetry ACP = 0.31+/-0.13+/-0.03. We observe B+ -> f0(980) K*+ and measure the branching fraction Br(B+ -> f0(980) K*+) x Br(f0(980) -> pi+pi-) = (4.2+/-0.6+/-0.3) x 10^{-6} and the CP-violation asymmetry ACP = -0.15+/-0.12+/-0.03. The first uncertainty quoted is statistical and the second is systematic.