Renormalizations in the nonlinear chiral theory

The renormalization program for nonlinear chiral theory is developed by using the superpropagator method. A number of relations between the renormalization constants (the Ward identities) is derived from the requirement of the chiral invariance. The strong πN coupling constant and the axial coupling constant of β-decay in the one-loop approximation and the two-loop corrections to the pion self-energy are calculated. The calculations show that in spite of the strong πN coupling the contributions from higher orders are relatively small (approximately 20-30%)