# Quenched Chiral Perturbation Theory for Heavy-light Mesons

## TL;DR

This paper develops quenched chiral perturbation theory for heavy-light mesons, calculating one-loop corrections and analyzing the limitations of quenched approximations in studying chiral limits.

## Contribution

It formulates quenched and partially quenched chiral perturbation theories for heavy-light mesons and computes relevant one-loop corrections.

## Key findings

- Chiral logarithms diverge in the quenched limit.
- Quenched theories should not be used to study the chiral limit.
- Ratios can reduce uncertainties in quenching errors.

## Abstract

We formulate quenched chiral perturbation theory for heavy-light mesons coupled to pions, and calculate the one-loop chiral logarithmic corrections to $f_B$, $f_{B_{s}}$, $B_B$ and $B_{B_{s}}$. We also calculate these corrections for ``partially quenched'' theories. In both theories, the chiral logarithms diverge in the chiral limit, indicating that (partially) quenched theories should not be used to study this limit. Comparing the chiral logarithms to those in QCD, we estimate the errors caused by (partial) quenching. By forming suitable ratios, we can reduce the uncertainties in our estimates.