Limits on Cosmic Chiral Vortons

Abstract

We study chiral vorton production for Witten-type superconducting string models in the context of a recently developed analytic formalism. We delineate three distinct scenarios: First, a low energy regime (including the electroweak scale) where vortons can be a source of dark matter. Secondly, an intermediate energy regime where the vorton density is too high to be compatible with the standard cosmology (thereby excluding these models). Finally, a high energy regime (including the GUT scale) in which no vortons are expected to form. The vorton density is most sensitive to the order of the string-forming phase transition and relatively insensitive to the current-forming transition. For a second-order string transition, vorton production is cosmologically disastrous for the range $10^{-28}\lsim Gμ\lsim 10^{-10}$ ($10^{5} GeV \lsim T_{c} \lsim 10^{14} GeV$), while for the first-order case we can only exclude $10^{-20}\lsim Gμ\lsim 10^{-14}$ ($10^{9} GeV \lsim T_{c} \lsim 10^{12} GeV$). We provide a fitting formula which summarises our results.

9 LaTeX pages, 5 .eps files; submitted to Phys.Lett.B