Bulk vibrations and twists in global cosmic strings

The Higgs fields surrounding loops of global cosmic strings contain the major component of the loop energy [E ≈ R ln (R/λ)]. These Higgs fields can undergo bulk vibrations and we demonstrate that these vibrations have a frequency which is larger, by a factor of ln(R/λ), than that of previously considered oscillations of strings. These bulk modes should dominate the processes of radiation emission. We also study configurations where a string threads a loop. Both strings are twisted. Twisted global strings usually have an energy which grows as R_CUTOFF², but in the above configuration we find the boundary conditions eliminate this extra energy. The final energy is just the sum of the energies of the untwisted loop and the untwisted string, with no interaction energy. The absence of interaction energy suggests that the twists may play an important role in the interaction of global strings, at least when one of the strings is a loop.