Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
The decay constants of the charmed heavy pseudoscalar D and D_s mesons are
revisited within a recently developed novel approach to dispersive QCD sum
rules which relies on an unprejudiced implementation of quark-hadron duality.
The proposed modification of the conventional sum-rule techniques is assessed
by applying our prescriptions to quantum mechanics, where exact solutions may
be easily obtained by simply solving the Schr\"odinger equation. The very
striking similarity of the extraction procedures of bound-state parameters in
potential models and in QCD gives us great confidence in the reliability of our
improvements of the sum-rule formalism and their applicability to hadron
phenomenology. The implications of one's chosen definition of the heavy-quark
masses are scrutinized and the MS-bar quark-mass scheme is identified as the
optimal choice for our purposes. Our ideas turn out to reconcile QCD sum-rule
predictions for the charmed-meson decay constants (which before tended to be
markedly too low) with the findings of both lattice QCD and experiment.
View original:
http://arxiv.org/abs/1108.0844
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