Study of Polarization in B -> VT Decays

TL;DR

This paper investigates the polarization patterns in B -> VT decays, comparing experimental measurements with theoretical predictions, and explores implications for the standard model and new physics scenarios.

Contribution

It provides the first detailed polarization analysis of B -> VT decays and examines how different models can explain the observed polarization fractions.

Findings

fT/fL ratio is small in B ->  K_2^* decays

Naive SM predicts fT/fL << 1, but extensions like penguin annihilation and rescattering do not make firm predictions

New physics scenarios can match data if certain form factor hierarchies are assumed

Abstract

In this paper, we examine B -> VT decays (V is a vector and T is a tensor meson), whose final-state particles can have transverse or longitudinal polarization. Measurements have been made of B -> \phi K_2^*, and it is found that fT/fL is small, where fT (fL) is the fraction of transverse (longitudinal) decays. We find that the standard model (SM) naively predicts that fT/fL << 1. The two extensions of the naive SM which have been proposed to explain the large fT/fL in B -> \phi K^* -- penguin annihilation and rescattering -- make no firm predictions for the polarization in B -> \phi K_2^*. The two new-physics scenarios, which explain the data in B -> \pi K and the \phi (\rho) K^* polarization measurements, can reproduce the fT/fL data in B -> \phi K_2^* only if the B -> T form factors obey a certain hierarchy. Finally, we present the general angular analysis which can be used to get helicity information using two- and three-body decays.