The phase transition associated with intermediate gauge symmetry breaking in superstring models

Abstract

Characteristic features of the phase transition associated with the intermediate gauge symmetry breaking in superstring models are investigated. The action of O(3)-symmetric bounce solution at a temperature T ⪢ m is estimated as 3 T ∼(T/m) 3 , where m is the scale of the effective soft supersymmetry breakings. Since the tunneling effect seems negligible for T⪢ m, the critical temperature for the phase transition will be of O( m). After the phase transition, a large amount of entropy could be produced by the decay of Higgs particles with the reheating temperature ⪅10 5 GeV unless the gauge symmetry breaking scale M 1 is small enough, e.g. M I⪅10 7 GeV for m⪅10 3 GeV to satisfy S f S i ⪅10 6 . A possible baryogenesis due to the Higgs particle decay is also suggested.