It is shown that a 25(20)% difference between the decay constants fDs(fBs) and fD(fB) occurs due to large differences in the pole masses of the s and d(u) quarks. The values ηD=fDs/fD≈1.23(15), recently observed in the CLEO experiment, and ηB=fBs/fB≈1.20, obtained in unquenched lattice QCD, can be reached only if the running mass ms at low scale is ms(∼0.5 GeV)=170−200 MeV. Our results follow from the analytical expression for the pseudoscalar decay constant fP based on the path-integral representation of the meson Green's function.
@article{arxiv.hep-ph/0702229,
title = {The running mass $m_s$ at low scalefrom the heavy-light meson decay constants},
author = {A. M. Badalian and B. L. G. Bakker},
journal= {arXiv preprint arXiv:hep-ph/0702229},
year = {2015}
}