Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy-light mesons

Autor(en)
Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
Abstrakt

We discuss the leptonic decay constants of heavy-light mesons by means of Borel QCD sum rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all vacuum-condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective threshold. We study properties of the LD effective thresholds in the limits of large heavy-quark mass mQ and small light-quark mass m(q). In the heavy-quark limit, we clarify the role played by the radiative corrections in the effective threshold for reproducing the pQCD expansion of the decay constants of pseudoscalar and vector mesons. We show that the dependence of the meson decay constants on mq arises predominantly (at the level of 70-80%) from the calculable mq-dependence of the perturbative spectral densities. Making use of the lattice QCD results for the decay constants of nonstrange and strange pseudoscalar and vector heavy mesons, we obtain solid predictions for the decay constants of heavy-light mesons as functions of mq in the range from a few to 100 MeV and evaluate the corresponding strong isospin-breaking effects: f(D+) - f(D0) = (0.96 +/- 0.09) MeV, f(D*+) - f(D*0) = (1.18 +/- 0.35) MeV, f(B0) - f(B+) = (1.01 +/- 0.10) MeV, f(B*0) - f(B*+) = (0.89 +/- 0.30) MeV.

Organisation(en)
Teilchenphysik
Externe Organisation(en)
Österreichische Akademie der Wissenschaften (ÖAW), Lomonosov Moscow State University (MSU), Istituto Nazionale di Fisica Nucleare (INFN), Roma, Universität Wien
Journal
European Physical Journal C
Band
78
Anzahl der Seiten
12
ISSN
1434-6044
DOI
https://doi.org/10.1140/epjc/s10052-018-5637-z
Publikationsdatum
02-2018
Peer-reviewed
Ja
ÖFOS 2012
103034 Teilchenphysik
Schlagwörter
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/localduality-qcd-sum-rules-for-strong-isospin-breaking-in-the-decay-constants-of-heavylight-mesons(f1e7446f-e1dd-493b-9895-aad8e80638c3).html