NEW CLASS OF HANBURY-BROWN-TWISS PARAMETERS

In heavy ion collisions resonances can create strong non-Gaussian effe cts in the two-pion correlation function. Hence, the commonly used Gau ssian fit parameters do not fully characterize these correlators. We s uggest a different set of HBT parameters which does not presuppose a p articular shape of the correlator and allows one to extract additional information not contained in the Gaussian fit parameters. Within a si mple model for an expanding source including resonance decays it is sh own that this additional information provides a clean distinction betw een scenarios with and without transverse flow.