Electroweak pion-nucleon constant

The parity-violating pion-nucleon coupling constant for the neutral currents of electroweak interaction is calculated by the method of QCD sum rules. In doing this, operators up to dimension 5 are retained in the operator-product expansion for the correlation function in an external pion field. That the value obtained for the pion-nucleon coupling constant is comparatively small stems from a partial cancellation between the leading perturbative and condensate contributions. This constant is compared with experimental data and with the results of calculations pet-formed by other authors. (C) 2002 MAIK Nauka/Interperiodica.