Searching for chiral logs in the static-light decay constant

TL;DR

This study investigates the presence of chiral logarithmic behavior in the static-light decay constant within unquenched QCD, using different static actions and analyzing their implications for chiral perturbation theory.

Contribution

It compares static-light decay constant data from different static actions to assess evidence for chiral logs and discusses their theoretical significance.

Findings

Evidence for chiral logs with the original static theory of Eichten and Hill.

No evidence for non-linear dependence in more precise ALPHA collaboration data.

Comments on the connection between chiral perturbation theory for pions and static-light mesons.

Abstract

Using the clover fermion action in unquenched QCD with pion masses as low as 420 MeV, we look for evidence for chiral logs in the static-light decay constant. There is some evidence for a chiral log term, if the original static theory of Eichten and Hill is used. However, the more precise data from the static action of the ALPHA collaboration do not show any evidence for non-linear dependence of the static-light decay constant on the light quark mass. We make some comments on the connection between chiral perturbation theory for decay constants of the pion and static-light meson.