Decay Constants of Beauty Mesons from QCD Sum Rules · arXivDesk
1410.6684Oct 24, 20146 pages, 2 figures, talk presented at "QCD@Work 2014 - International Workshop on Quantum Chromodynamics: Theory and Experiment" (16 - 19 June 2014, Giovinazzo, Bari, Italy)
Decay Constants of Beauty Mesons from QCD Sum Rules
Our recently completed analysis of the decay constants of both pseudoscalar and vector beauty mesons reveals that in the bottom-quark sector two specific features of the sum-rule predictions show up: (i) For the input value of the bottom-quark mass in the MS scheme m_b(m_b)≈4.18 GeV, the sum-rule result fB≈210-220 MeV for the B
Nearby in the stack
meson decay constant is substantially larger than the recent lattice-QCD finding
f_B≈190 MeV.
Requiring QCD sum rules to reproduce the lattice-QCD value of
fB
yields a significantly larger
b
-quark mass:
m_b(m_b)=4.247 GeV.
(ii) Whereas QCD sum-rule predictions for the charmed-meson decay constants
fD,
fDs,
fD∗
and
fDs∗
are practically independent of the choice of renormalization scale, in the beauty sector the results for the decay constants - and especially for the ratio
fB∗/fB
- prove to be very sensitive to the specific scale setting.