Charm couplings and form factors in QCD sum rules

TL;DR

This paper reviews the calculation of charm meson form factors and coupling constants using QCD sum rules, with applications to heavy ion collisions, B decays, and specific reaction cross sections.

Contribution

It provides a comprehensive overview of QCD sum rule techniques for charm mesons, including parametrizations, uncertainties, and comparisons with other methods.

Findings

Parametrizations of form factors for charm mesons are provided.

Coupling constants are estimated and compared with other approaches.

Application to the $J/ heta + \pi ightarrow D + ar{D^*}$ reaction cross section.

Abstract

We review the calculations of form factors and coupling constants in vertices with charm mesons in the framework of QCD sum rules. We first discuss the motivation for this work, describing possible applications of these form factors to heavy ion collisions and to B decays. We then present an introduction to the method of QCD sum rules and describe how to work with the three-point function. We give special attention to the procedure employed to extrapolate results obtained in the deep euclidean region to the poles of the particles, located in the time-like region. We present a table of ready-to-use parametrizations of all the form factors, which are relevant for the processes mentioned in the introduction. We discuss the uncertainties in our results. We also give the coupling constants and compare them with estimates obtained with other methods. Finally we apply our results to the calculation of the cross section of the reaction $J/\psi + \pi \rightarrow D + \bar{D^*}$.