Measurement of the Decay Amplitudes of B0 --> J/psi K* and B0s --> J/psi phi Decays

TL;DR

This paper presents a detailed angular analysis of B0 and B_s meson decays into J/psi and vector mesons, measuring decay amplitudes and polarization states using data from Fermilab Tevatron.

Contribution

It provides the first comprehensive measurement of decay amplitudes and polarization fractions for B0 --> J/psi K* and B_s --> J/psi phi decays using Tevatron data.

Findings

Longitudinal polarization amplitude dominates

Parity-odd transverse polarization is small

Results support theoretical predictions of decay dynamics

Abstract

A full angular analysis has been performed for the pseudo-scalar to vector-vector decays, B0 --> J/psi K* and B_s --> J/psi phi, to determine the amplitudes for decays with parity-even longitudinal and transverse polarization and parity-odd transverse polarization. The measurements are based on 190 B0 candidates and 40 B_s candidates collected from a data set corresponding to 89 inverse pb of pbarp collisions at root(s) = 1.8 TeV at the Fermilab Tevatron. In both decays the decay amplitude for longitudinal polarization dominates and the parity-odd amplitude is found to be small.