The $K^{\ast }K\pi$ and $\rho \pi \pi$ couplings in QCD

Abstract

The light cone QCD sum rules are derived for the $K^{\ast }K\pi$ coupling $g_{K^{\ast }K\pi }$ and the $\rho \pi \pi$ coupling $g_{\rho \pi \pi }$. 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 $g_{K^{\ast }K\pi }=(8.7\pm 0.5)$ and $g_{\rho \pi \pi }=(11.5\pm 0.8)$ is in good agreement with the experimental value.

Comments: 7 pages + 2 PS figures, submitted to Euro. Phys. J. A