Isospin breaking in the decay constants of heavy mesons from QCD sum rules
- Author(s)
- Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
- Abstract
We present a study of the strong isospin-breaking (IB) effect, due in QCD to the difference between u- and d-quark masses, in the leptonic decay constants of charmed and beauty pseudoscalar and vector mesons using the method of QCD sum rules. We apply the sum-rule analysis to the decay constants of mesons containing one heavy quark and one light quark with the light mass in the range from the average u/d quark mass to the strange-quark mass. We then analyse the dependence of the decay constants on the light-quark mass and extract with good accuracy the IB ratios of decay constants at leading order in the mass difference (m(d) - m(u)), obtaining: (f(D)+ - fD(0))/fD = 0.0047(6), (f(D*+) - f(D*o))/fD* = 0.0068(9), (fB(0) - f(B+))/f(B) = 0.0047(6), and (f(B*0) - f(B*+))/f(B*) = 0.0045(5), which yield: f(D+) - f(D0) = 0.97 +/- 0.13 MeV, f(D*+) - f(D*0) = 1.73 +/- 0.27 MeV, f(B0) - f(B+) = 0.90 +/- 0.13 MeV, f(B*0) - f(B*+) = 0.81 +/- 0.11 MeV. In the case of the D-meson our finding is consistent with recent lattice QCD results, whereas it is much lower in the case of the B-meson showing a tension of approximate to 3 standard deviations. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.
- Organisation(s)
- Particle Physics
- External organisation(s)
- Österreichische Akademie der Wissenschaften (ÖAW), Lomonosov Moscow State University (MSU), Universität Wien, Istituto Nazionale di Fisica Nucleare (INFN), Roma
- Journal
- Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics
- Volume
- 765
- Pages
- 365-370
- No. of pages
- 6
- ISSN
- 0370-2693
- DOI
- https://doi.org/10.1016/j.physletb.2016.12.041
- Publication date
- 02-2017
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103012 High energy physics
- Keywords
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/isospin-breaking-in-the-decay-constants-of-heavy-mesons-from-qcd-sum-rules(4a6248e4-3c83-4e32-acb6-7d5235c04008).html