Amplitude Analysis of the B+- ->phi K*(892)+- Decay

TL;DR

This study conducts a detailed amplitude analysis of the B+- -> phi K*(892)+- decay, measuring multiple parameters to understand the decay dynamics and CP-violation effects using a large data sample.

Contribution

It provides the first comprehensive measurement of decay amplitudes, phases, and CP-violation parameters for this decay mode, resolving phase ambiguities with interference analysis.

Findings

Measured longitudinal fraction f_L=0.49+-0.05+-0.03

Found transverse fraction f_perp=0.21+-0.05+-0.02

Detected a substantial helicity-plus amplitude from unknown sources

Abstract

We perform an amplitude analysis of B+- -> phi(1020) K*(892)+- decay with a sample of about 384 million BBbar pairs recorded with the BABAR detector. Overall, twelve parameters are measured, including the fractions of longitudinal f_L and parity-odd transverse f_perp amplitudes, branching fraction, strong phases, and six parameters sensitive to CP-violation. We use the dependence on the Kpi invariant mass of the interference between the JP=1- and 0+ Kpi components to resolve the discrete ambiguity in the determination of the strong and weak phases. Our measurements of f_L=0.49+-0.05+-0.03, f_perp=0.21+-0.05+-0.02, and the strong phases point to the presence of a substantial helicity-plus amplitude from a presently unknown source.