Lattice measurement of the Isgur-Wise functions tau_1/2 and tau_3/2

TL;DR

This paper introduces a lattice method to compute Isgur-Wise form factors for B meson decays into excited D** mesons, providing preliminary numerical results that align with theoretical predictions.

Contribution

It presents a novel lattice approach to calculate specific Isgur-Wise functions tau_1/2 and tau_3/2 at zero recoil for B to D** decays.

Findings

Tau_1/2(1)=0.38(5)

Tau_3/2(1)=0.53(8)

Results agree with theoretical expectations

Abstract

We propose a method to compute the Isgur-Wise form factors tau_1/2(1) and tau_3/2(1) for the decay of B mesons into orbitally excited (P wave) D** charmed mesons on the lattice in the static limit. We also present the result of an exploratory numerical simulation which shows that the signal/noise ratio allows for a more dedicated computation. We find tau_1/2(1)=0.38(5) and tau_3/2(1)= 0.53(8), with yet unknown systematic errors. These preliminary numbers agree fairly well with theoretical expectation.