A fresh look into m_{c,b} and precise f_{D_(s),B_(s)} from heavy-light   QCD spectral sum rules
  Using recent values of the QCD (non-) perturbative parameters given in Table 1 and an estimate of the N3LO QCD perturbative contributions based on the geometric growth of the PT series, we re-use QCD spectral sum rules (QSSR) known to N2LO PT series and including all dimension-six NP condensate contributions in the full QCD theory, for improving the existing estimates of {m}_{c,b} and f_{D_(s)}, f_{B_(s)} from the open charm and beauty systems. We especially study the effects of the subtraction point on "different QSSR data" and use (for the first time) the Renormalization Group Invariant (RGI) scale independent quark masses in the analysis. The estimates [rigourous model-independent upper bounds within the SVZ framework] reported in Table 8: f_D/f_\pi=1.56(5)[< 1.68(1)], f_B/f_\pi=1.58(5)[< 1.80(3)] and f_{D_s}/f_K= 1.58(4) [< 1.63(1)], f_{B_s}/f_K=1.50(3)[< 1.61(3.5)], which improve previous QSSR estimates, are in perfect agreement (in values and precisions) with some of the experimental data on f_{D,D_s} and on recent lattice simulations within dynamical quarks. These remarkable agreements confirm both the success of the QSSR semi-approximate approach based on the OPE in terms of the quark and gluon condensates and of the Minimal Duality Ansatz (MDA) for parametrizing the hadronic spectral function which we have tested from the complete data of the J/\psi and \Upsilon systems. The values of the running quark masses m_c(m_c)=1286(66) MeV and m_b(m_b)= 4236(69) MeV from M_{D,B} are in good agreement though less accurate than the ones from recent J/\psi and \Upsilon sum rules. 
Stephan Narison (LUPM-CNRS/IN2P3, Montpellier-FR)
hep-ph hep-ex hep-lat