Cosmic string loops collapsing to black holes

We examine the question of collapse of Turok's two-parameter family of cosm ic strings. We first perform a classification of the strings according to t he specific time(s) at which the minimal string size is reached during one period. We then obtain an exact analytical expression for the probability o f collapse to black holes for the Turok strings. Our result has the same ge neral behavior as previously obtained in the literature but we find, in add ition, a numerical prefactor that changes the result by three orders of mag nitude. Finally we show that our careful computation of the prefactor helps us to understand the discrepancy between previously obtained results and, in particular, that for "large" values of G mu, there may not even be a dis crepancy. We also give a simple physical argument that can immediately rule out some of the previously obtained results.