Prof. Dejan Stojkovic, SUNY at Buffalo, visited SCL and gave a seminar on electroweak stars.The seminar gave an excelent pedagogical exposition of the life-cycle of stars. The focus of the talk was a discussion of electroweak stars, a newly proposed phase at the end of the stellar life-cycle. Electroweak stars would be compact stellar-mass objects whose central core temperature is higher than the electroweak symmetry restoration temperature. These object would be fueled by non-perturbative baryon number (B) and lepton number (L) violating processes within the standard-model. These processes allow the chemical potential of B+L to relax to zero. The energy released at the core would be enormous, but gravitational redshift and the enhanced neutrino interaction cross sections at these energies would make the energy release rate moderate at the surface of the star. The lifetime of this new quasi-equilibrium would be more than ten million years, long enough to represent a distinct new stage in the evolution of a star.

The seminar led to an interesting discussion session that focused both on the underlying microphysics fueling electroweak stars, as well as the observable consequences of the existence of this proposed phase in the death of a star. Prof. Stojkovic's stay at SCL also lead to a number of additional improptu discussions on several other topics in early universe cosmology and black-hole physics.