CP(N-1) model on a disk and decay of a non-Abelian string

We consider the role of quantum effects in the nonperturbative decay of the non-Abelian string with orientational moduli in nonsupersymmetric D = 4 gauge theory. To this aim the effective action in the CP(N - 1) model on a disk at large N has been calculated. It exhibits a phase transition at some radius, the "wrong sign" Luscher term, and a large boundary boojumlike negative contribution. The effect of the theta term and the possibility of the spontaneous creation of the non-Abelian string are briefly discussed.