  We calculate the probability of destruction of a metastable string by
collisions of the Goldstone bosons, corresponding to the transverse waves on
the string. We find a general formula that allows to determine the probability
of the string breakup by a collision of arbitrary number of the bosons. We find
that the destruction of a metastable string takes place only in collisions of
even number of the bosons, and we explicitly calculate the energy dependence of
such process in a two-particle collision for an arbitrary relation between the
energy and the largest infrared scale in the problem, the length of the
critical gap in the string.
