Analysis of the strong coupling constant and the decay width of with QCD sum rules
Abstract
In this article, we calculate the form factors and the coupling constant of the vertex using the threepoint QCD sum rules. We consider the contributions of the vacuum condensates up to dimension 7 in the operator product expansion. And all possible offshell cases are considered, , and , resulting in three different form factors. Then we fit the form factors into analytical functions and extrapolate them into timelike regions, which giving the coupling constant for the process. Our analysis indicates that the coupling constant for this vertex is . The results of this work are very useful in the other phenomenological analysis. As an application, we calculate the coupling constant for the decay channel and analyze the width of this decay with the assumption of the vector meson dominance of the intermediate . Our final result about the decay width of this decay channel is.
 Publication:

European Physical Journal C
 Pub Date:
 June 2015
 DOI:
 10.1140/epjc/s1005201534603
 arXiv:
 arXiv:1502.01698
 Bibcode:
 2015EPJC...75..243Y
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 arXiv admin note: text overlap with arXiv:1501.03088 by other authors