Ground-State Extraction of Heavy-Light Meson Semileptonic Decay Form Factors

TL;DR

This paper develops methods to accurately extract semileptonic decay form factors of heavy-light mesons from lattice QCD simulations, addressing excited state contamination and combining different theoretical limits.

Contribution

It introduces an improved analysis technique for extracting decay form factors from lattice data, incorporating summed ratios and chiral perturbation theory inputs.

Findings

Successful extraction of decay form factors from four CLS ensembles.

Effective suppression of excited state contamination.

Framework for combining relativistic and static-limit results.

Abstract

We discuss the extraction of heavy-light pseudo-scalar to light pseudo-scalar decay form factors from finite time correlation functions. We place particular emphasis on the contamination from excited states employing summed ratios and input from chiral perturbation theory. The analysis is performed on four CLS ensembles with $N_f = 2+1$ flavours of $\mbox{O}(a)$-improved Wilson fermions (presently) at the $\mathrm{SU}(3)$-symmetric point with relativistic heavy-quark masses in the charm region and above. The study presented here is part of the analysis aimed at the computation of the $B \to \pi \ell \nu$ and $B_s \to K \ell \nu$ semileptonic form factors, combining the continuum-limit relativistic results with static-limit calculations.