Using QCD sum rules, we compute the diagonal meson-baryon couplings, πNN , ηNN , πΞΞ , ηΞΞ , πΣΣ and ηΣΣ , from the baryon-baryon correlation function with a meson: i∫d4xeiq·x〈0TJB(x)J̄ B(0)M(p)〉 . The calculations are performed to leading order in pμ by considering the two separate Dirac structures, iγ5γμpμ and γ5σμνqμpν separately. We first improve the previous sum rule calculations on these Dirac structures for the πNN coupling by including three-particle pion wave functions of twist 4 and then extend the formalism to calculate the other couplings, ηNN , πΞΞ , ηΞΞ , πΣΣ and ηΣΣ . In the SU(3) symmetric limit, we identify the terms responsible for the F/D ratio in the OPE by matching the obtained couplings with their SU(3) relations. Depending on the Dirac structure considered, we find different identifications for the F/D ratio. The couplings including the SU(3) breaking effects are also discussed within our approach.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics