In the simplest extension of the minimal supersymmetric model, it is shown that there is a range of parameters for which the scalar top quark acquires a vacuum expectation value during a brief period after the onset of the electroweak phase transition. In this case, electromagnetism is temporarily broken, causing efficient annihilation of magnetic monopoles. Also, the temporary spontaneous violation of baryon number may have interesting consequences for models of electroweak baryogenesis.

• Received 8 June 1992

DOI:https://doi.org/10.1103/PhysRevD.46.4775