The $\eta NN$ coupling constant

Abstract

We derive the light cone QCD sum rule for the $\eta NN$ coupling constant $g_{\eta NN}$. The contribution from the excited states and the continuum is subtracted cleanly through the double Borel transform with respect to the two external momenta, $p_1^2$, $p_2^2=(p-q{)}^2$. Our result is ${\alpha }_{\eta NN}=(0.3\pm 0.15)$, which favors small values used in literatures.

Comments: RevTex, two figures, discussions added, Phys. Rev. C (in press)