Coupling constants of bottom (charmed) mesons with the pion from three-point QCD sum rules

M Janbazi,E Pourjafarabadi,N Ghahramany

doi:10.1140/epjc/s10052-014-2718-5

M Janbazi, E Pourjafarabadi + Show 1 more

Open Access

https://doi.org/10.1140/epjc/s10052-014-2718-5

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Abstract

In this article, the three point QCD sum rules is used to compute the strong coupling constants of vertices containing the strange bottomed ( charmed ) mesons with pion. The coupling constants are calculated, when both the bottom ( charm ) and pion states are off-shell. A comparison of the obtained results of coupling constants with the existing predictions is also made. Key words: strong coupling constant, meson, QCD sum rules, bottom, charm.

Highlights

D∗ D∗ρ [10], D D J/ψ [11], D∗ D J/ψ [12], D∗ D∗ J/ψ [13], Ds D∗ K, Ds∗ D K [14], D Dω [15] and V Ds∗0 Ds∗0, V Ds Ds, V Ds∗ Ds∗, and V Ds1 Ds1 [16], in the framework of three-point QCD sum rules
We focus on the method of three-point QCD sum rules (QCDSR) to calculate the strong form factors and coupling constants associated with the B1 B∗π, B1 B0π, B1 B1π, D1 D∗π, D1 D0π, and D1 D1π vertices, for both the bottom and the pion states being off-shell
In QCD or the theoretical part, which consists of two contributions, perturbative and non-perturbative, we evaluate the correlation function in quark–gluon language and in terms of QCD degrees of freedom, such as the quark condensate, the gluon condensate, etc., with the help of the Wilson operator product expansion (OPE)

Summary

Introduction

D∗ D∗ρ [10], D D J/ψ [11], D∗ D J/ψ [12], D∗ D∗ J/ψ [13], Ds D∗ K , Ds∗ D K [14], D Dω [15] and V Ds∗0 Ds∗0, V Ds Ds , V Ds∗ Ds∗, and V Ds1 Ds1 [16], in the framework of three-point QCD sum rules. We focus on the method of three-point QCDSR to calculate the strong form factors and coupling constants associated with the B1 B∗π , B1 B0π , B1 B1π , D1 D∗π , D1 D0π , and D1 D1π vertices, for both the bottom (charm) and the pion states being off-shell. In QCD or the theoretical part, which consists of two contributions, perturbative and non-perturbative (in the present work the calculations contributing the quark–quark and quark–gluon condensate diagrams are considered as non-perturbative effects), we evaluate the correlation function in quark–gluon language and in terms of QCD degrees of freedom, such as the quark condensate, the gluon condensate, etc., with the help of the Wilson operator product expansion (OPE). 2, by introducing the sufficient correlation functions, we obtain QCD sum rules for the strong coupling constant of the considered B1 B∗π , B1 B0π , and B1 B1π vertices. 3, the obtained sum rules for the considered strong coupling constants are numerically analysed. We compare our results with the existing predictions of other work

The three-point QCD sum rules method

Numerical analysis

Findings

Conclusion