Decay constants of heavy pseudoscalar mesons from QCD sum rules

Author(s): Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
Abstract: We revisit the sum-rule extraction of the decay constants of the D, D(s), B and B(s) mesons from the two-point correlator of heavy-light pseudoscalar currents. We use the operator product expansion of this correlator expressed in terms of the (MS) over bar heavy-quark mass for which the perturbative expansion exhibits a reasonable convergence. Our main emphasis is laid on the control over the uncertainties in the decay constants, related both to the input quantum chromodynamics (QCD) parameters and to the limited intrinsic accuracy of the method of QCD sum rules. This becomes possible due to the application of our procedure of extracting hadron observables that involves as novel feature dual thresholds depending on the Borel parameter. For charmed mesons, we find the decay constants f(D) = (206.2 +/- 7.3((OPE)) +/- 5.1((syst))) MeV and f(Ds) = (245.3 +/- 15.7((OPE)) +/- 4.5((syst))) MeV. For beauty mesons, the decay constants turn out to be extremely sensitive to the precise value of (m) over bar (b)((m) over bar (b)). By requiring our sum-rule estimate to match the average of the lattice results for f(B), a very accurate value (m) over bar (b)((m) over bar (b)) = (4.245 +/- 0.025) GeV is extracted, leading to f(B) = (193.4 +/- 12.3((OPE)) +/- 4.3((syst))) MeV and f(Bs) = (232.5 +/- 18.6((OPE)) +/- 2.4((syst))) MeV.
Organisation(s): Particle Physics
External organisation(s): Istituto Nazionale di Fisica Nucleare (INFN), Roma, Österreichische Akademie der Wissenschaften (ÖAW), Anuchin Research Institute and Museum of Anthropology
Journal: Journal of Physics G: Nuclear and Particle Physics
Volume: 38
No. of pages: 17
ISSN: 0954-3899
DOI: https://doi.org/10.1088/0954-3899/38/10/105002
Publication date: 2011
Peer reviewed: Yes
Austrian Fields of Science 2012: 103014 Nuclear physics
Portal url: https://ucrisportal.univie.ac.at/en/publications/200de5c5-f198-4d84-9f45-d17ef51048ce