On the B*' --> B transition

TL;DR

This paper provides the first lattice QCD estimate of the hadronic coupling g_12 for B* meson decay, using HQET and GEVP methods, with results extrapolated to the continuum limit.

Contribution

It introduces a novel lattice calculation of g_12 in the static limit of HQET, including continuum extrapolation and pion mass dependence analysis.

Findings

g_12 = -0.17(4) after extrapolation

First lattice estimate of this coupling in Nf=2 QCD

Methodology combining GEVP and HQET used successfully

Abstract

We present a first Nf=2 lattice estimate of the hadronic coupling g_12 which parametrises the strong decay of a radially excited B* meson into the ground state B meson at zero recoil. We work in the static limit of Heavy Quark Effective Theory (HQET) and solve a Generalised Eigenvalue Problem (GEVP), which is necessary for the extraction of excited state properties. After an extrapolation to the continuum limit and a check of the pion mass dependence, we obtain g_12 = -0.17(4).