Omega meson as a chronometer and thermometer in hot-dense hadronic   matter
  Changes in the properties of the vector mesons in hot and dense hadronic matter, as produced in heavy ion collisions, lead to the intriguing possibility of the opening of the decay channel $\omega \ra \rho \pi$, for the omega meson, which is impossible in free space. This along with the channel $\omega \pi \ra \pi \pi$ would result in a decrease in its effective life-time enabling it to decay within the hot zone and act as a chronometer in contradiction to the commonly held opinion and would have implications vis a vis determination of the size of the region through pion interferometry. A new peak and a radically altered shape of the low invariant mass dilepton spectra appears due to different shift in the masses of $\rho$ and $\omega$ mesons. The Walecka model is used for the underlying calculation for the sake of illustration. 
Pradip Roy, Sourav Sarkar, Jan-e Alam, Binayak Dutt-Roy and Bikash   Sinha