Decay constants of heavy pseudoscalar mesons from QCD sum rules

Autor(en)

Wolfgang Lucha, Dmitri Melikhov, Silvano Simula

Abstrakt

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(en)

Teilchenphysik

Externe Organisation(en)

Istituto Nazionale di Fisica Nucleare (INFN), Roma, Österreichische Akademie der Wissenschaften (ÖAW), Lomonosov Moscow State University (MSU)

Journal

Journal of Physics G: Nuclear and Particle Physics

Band

38

Anzahl der Seiten

17

ISSN

0954-3899

DOI

https://doi.org/10.1088/0954-3899/38/10/105002

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

103014 Kernphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/200de5c5-f198-4d84-9f45-d17ef51048ce