The suppression of $\pi N N(1535)$ coupling in QCD

Abstract

The light cone QCD sum rules are employed to calculate the $\pi N N(1535)$ coupling $g_{\pi N N^\ast}$. We study the two point correlation function of two nucleon currents sandwiched between the vacuum and the pion state. The contribution from the excited states and the continuum is subtracted cleanly through double Borel transformation with respect to the nucleon and N(1535) momenta, $p_1^2$, $p_2^2=(p-q)^2$. Our calculation shows that the $\pi N N(1535)$ coupling is strongly suppressed.