Leptonic decay constants of charm and beauty mesons in QCD

Abstract

Leptonic decay constants of heavy pseudoscalar mesons are estimated in QCD by means of Hilbert transform power-moment sum rules at Q2=0. The meson masses are also obtained in order to assess the reliability of these predictions. Our results are ƒD/ƒπ=1.7±0.2, ƒFƒπ=2.1±0.1, and ƒB/ƒπ=1.1−1.6. As a byproduct a bound on ƒB/ƒB is obtained.