omega meson as a chronometer and thermometer in hot and dense hadronic matter

Changes in the properties of the vector mesons in hot and dense hadronic ma tter, as produced in heavy-ion collisions, lead to the intriguing possibili ty of the opening of the decay channel omega-->rho pi, for the omega meson, which is impossible in free space. This along with the channel omega pi--> pi pi would result in a decrease in its effective lifetime enabling it to d ecay within the hot zone and act as a chronometer in contradiction to the c ommonly held opinion and would have implications vis a vis determination of the size of the region through pion interferometry. A new peak and a radic ally altered shape of the low invariant mass dilepton spectra appears due t o different shifts in the masses of rho and omega mesons. The Walecka model is used for the underlying calculation for the sake of illustration. [S055 6-2813(99)02705-3].