Extracting m_c(M_c) and f_{D_s,B} from the pseudoscalar sum rules

Abstract

I report here on the (first) direct extraction of the running charm quark mass m_c(\nu) from the D-meson sum rules, and on the implications of this result for the estimate of the leptonic decay constants f_{D_s}. The outputs: m_c(M_c)=(1.08\pm 0.11) GeV, f_{D}= (1.52\pm 0.16)f_\pi, f_{D_s}= (1.75\pm 0.18)f_\pi and f_B=(1.44\pm 0.07)f_\pi are in good agreement with the existing sum rule results obtained using the pole mass. In particular, the result f_D\approx f_B supports early '87 sum rule results \cite{SNFB}, which indicated a huge 1/m correction to the heavy quark symmetry expectation. This talk is based on the paper hep-ph/9712386 and updates the discussions given there.