Constraints on cosmic strings due to black holes formed from collapsed cosmic string loops

The cosmological features of primordial black holes formed from collapsedcosmic string loops are studied. Observational restrictions on a population ofprimordial black holes are used to restrict $f$, the fraction of cosmic stringloops which collapse to form black holes, and $\mu$, the cosmic stringmass-per-unit-length. Using a realistic model of cosmic strings, we find thestrongest restriction on the parameters $f$ and $\mu$ is due to the energydensity in $100 MeV$ photons radiated by the black holes. We also find thatinert black hole remnants cannot serve as the dark matter. If earlier, crudeestimates of $f$ are reliable, our results severely restrict $\mu$, andtherefore limit the viability of the cosmic string large-scale structurescenario.Comment: (Plain Tex, uses tables.tex -- wrapped lines corrected), 11 pages, FERMILAB-Pub-93/137-