Meson loops and the gD*Dpi coupling

Abstract

The D * Dπ form factor is evaluated at low and moderate Q 2 in a hadronic loop model, for off-shell D mesons. The results contain arbitrary constants, which are fixed so as to match a previous QCD sum rule calculation valid at higher Q 2 . The form factor obtained in this way is used to extract the coupling constant, which is in very good agreement with the experimental value.

Strong and radiative decays of heavy mesons in a covariant model

“…For the strong couplings, our results are consistent with those of the experiment and QCD sum rules [52]. For the radiative decays, our results are close to the experimental data and the results of the light-front model [59] and the relativistic quark model [60].…”

“…The values of g V P π andĝ P compared with the experiment and other estimates are listed in table 6. Our strong couplings are consistent with those of the experiment and QCD sum rules [52]. As for the radiative decay, we use eq.…”

StrongD*→DπandB*→Bπcouplings

“…Based on Ref. [10], loop corrections in D-meson effective field theory have been used to constrain extrapolation of the D * Dπ coupling to physical momenta [11]. The simultaneous computation of both couplings has been completed in a dispersive quark model [12].…”

QCD sum rules approach to the X, Y and Z states

“…This idea was advanced in Ref. [167], and can be used to impose constraints that allow us to reduce the freedom of choice of the function parametrizing the QCDSR results in the deep Euclidean region.…”

“…The factorization of the amplitude allows the four-quark vertex to be analysed as two separated sub-processes: the creation of X(3872) and the transition B → K, as in Eqs. (166) and (167). Let us start with the two-point correlator, describing the coupling between the current J (cc) ν and X(3872):…”