How a quark-gluon plasma phase modifies the bounds on extra dimensions from SN1987a

The shape of the neutrino pulse from the supernova SN1987a provides one of the most stringent constraints on the size of large. compact, "gravity-only " extra dimensions. Previously, calculations have been carried out for a ne wly-born proto-neutron star with a temperature of about 50 MeV at nuclear m atter density. It is arguable that, due to the extreme conditions in the in terior of the star, matter might be a quark-gluon plasma. where the relevan t degrees of freedom are quarks and gluons rather than nucleons, We conside r an energy-loss scenario where seconds after rebounce the core of the star consists of a hot and dense quark-gluon plasma. Adopting a simplified mode l of the plasma we derive the necessary energy-loss formulae in the soft-ra diation limit. The emissivity is found to be comparable to the one for nucl ear matter and bounds on the radius of extra dimensions are similar to thos e found previously from nuclear matter calculations. (C) 2001 Elsevier Scie nce B.V. All rights reserved.