Implications from SN1987A on supersymmetric, left-right and E6 particle masses

Current extensions of the standard model contain extra particles that, if light, should be emitted in the course of stellar collapse. Using data on SN1987A, we place bounds on the mass of the heavy particles that mediate their production and rescattering in the stellar medium. Taking into account the uncertainties in the parameters of the stellar core, we find the following conservative lower bounds. The squarks and selectrons of supersymmetric theories, as well as the extra neutral gauge bosons of left-right symmetric models and of a variety of E6 superstring-inspired models, must all lie above the one TeV scale. One particular E6 model, however, evades our constraints. (orig.)