Abstract
The pion-nucleon and kaon-nucleon scattering lengths are calculated by means of Borel sum rules. The scattering lengths are related to the expectation values of correlation functions of the axial-vector currents with respect to the one-nucleon state by means of the reduction formula. We show that the pion-nucleon and kaon-nucleon scattering lengths are proportional to the quark number of the nucleon in the leading order of an operator product expansion, and rederive the Tomozawa-Weinberg relation.
