The F/D ratio and meson–baryon couplings from QCD sum rules II
✍ Scribed by Hungchong Kim; Takumi Doi; Makoto Oka; Su Houng Lee
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 257 KB
- Volume
- 678
- Category
- Article
- ISSN
- 0375-9474
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✦ Synopsis
Using QCD sum rules, we compute the diagonal meson-baryon couplings, πNN, ηNN, π , η , π and η , from the baryon-baryon correlation function with a meson: i d 4 x e iq•x 0|T J B (x) JB (0) |M(p) . The calculations are performed to leading order in p µ by considering the two separate Dirac structures, iγ 5 γ µ p µ and γ 5 σ µν q µ p ν 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, π , η , π and η . 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.