Heavy-Meson Decay Constants: QCD Sum-Rule Glance at Isospin Breaking

TL;DR

This paper compares QCD sum rules and lattice QCD in calculating heavy meson decay constants, highlighting differences in isospin breaking effects for B and D mesons.

Contribution

It provides a comparative analysis of QCD sum rules and lattice QCD results for heavy meson decay constants, focusing on isospin breaking effects.

Findings

QCD sum rules predict less isospin breaking for B mesons than lattice QCD.

Good agreement between methods for D mesons.

Highlights the differences in isospin breaking predictions between approaches.

Abstract

QCD sum rules for decay constants of heavy mesons with $u$ or $d$ quark yield for $B$ mesons much less isospin breaking than lattice QCD but good agreement for $D$ mesons.