Meson-Baryon Couplings Revisited

TL;DR

This paper recalculates meson-baryon coupling constants using QCD sum rules with polynomial kernels to improve stability, resulting in values close to experimental data and theoretical predictions.

Contribution

It introduces a new polynomial kernel method in QCD sum rules to reduce arbitrariness in calculating meson-baryon couplings.

Findings

Calculated coupling constants are close to experimental values.

Polynomial kernels improve stability over exponential kernels.

Results satisfy the Dashen-Weinstein relation.

Abstract

The theoretical evaluation of the coupling constants gpiNN , gKNLambda and gKNSigma is undertaken using QCD sum rules. These quantities were previously calculated with exponential (Borel) kernels used to suppress the unknown contributions of the hadronic continua. This method however introduces arbitrariness and instability in the calculation. In order to avoid these I redo the calculation using polynomial kernels tailored to vanish at the baryonic resonance masses. The results are gpiNN = 12.5 +- 1.0, gKNSigma = 5.45 +- .4, gKNSigma= -(12.7 - 15.0) which are close to experiment and to the predictions of SU(3) and which , with the corresponding Goldberger-Treiman Discrepancy satisfy quite well the Dashen-Weinstein relation.