$B\!\to\!D^{(*)}\ell\nu$ semileptonic decays in lattice QCD with domain-wall heavy quarks

TL;DR

This paper presents a lattice QCD calculation of $B o D^{(*)} \, \ell \nu$ form factors using relativistic domain-wall quarks across multiple lattice spacings, aiming to improve precision in semileptonic decay predictions.

Contribution

It introduces a novel lattice QCD approach employing M"obius domain-wall fermions for all quark flavors to compute form factors with controlled discretization effects.

Findings

Form factors extrapolated to continuum and physical quark masses.

Systematic uncertainties analyzed and discussed.

Results contribute to precision tests of the Standard Model.

Abstract

We calculate the $B \to D^{(*)} \ell \nu$ form factors in 2+1 flavor relativistic lattice QCD by employing the M\"obius domain-wall action for all quark flavors. Our simulations are carried out at lattice cut-offs $a^{-1} \sim 2.5$, 3.6 and 4.5 GeV with the bottom quark masses up to 0.7 $a^{-1}$ to control discretization effects. We extrapolate the form factors to the continuum limit and physical quark masses, and discuss systematic uncertainties of the form factors.