Eur. Phys. J. A (2015) 51: 28
https://doi.org/10.1140/epja/i2015-15028-9

Regular Article - Theoretical Physics

A QCD sum rules calculation of the J/ψD _s ^* D_s strong coupling constant

¹ Instituto de Física, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-900, Rio de Janeiro, RJ, Brazil
² Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Rod. Presidente Dutra Km 298, Pólo Industrial, 27537-000, Resende, RJ, Brazil

^* e-mail: bosorio@cbpf.br

Received: 21 September 2014
Revised: 16 February 2015
Accepted: 20 February 2015
Published online: 6 March 2015

Abstract

In this work, we calculate the form factors and the coupling constant of the strange-charmed vertex J/ψD _s ^* D _s in the framework of the QCD sum rules by studying their three-point correlation functions. All the possible off-shell cases are considered, D _s , D _s ^* and J/ψ, resulting in three different form factors. These form factors are extrapolated to the pole of their respective off-shell mesons, giving the same coupling constant for the process. Our final result for the J/ψD _s ^* D _s coupling constant is .