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We study the propagation of charm quarks, produced from the initial fusion of partons, in an equilibrating quark-gluon plasma which may be formed in the wake of relativistic collisions of gold nuclei. Initial conditions are taken from a self screened parton cascade model and the chemical equilibration is assumed to proceed via gluon multiplication and quark production. The energy loss suffered by the charm quarks is obtained by evaluating the drag force generated by the scattering with quarks and gluons in the medium. We find that the charm quarks may loose only about 10% of their initial energy in conditions likely to be attained at the Relativistic Heavy Ion Collider, while they may loose up to 40% of their energy while propagating in the plasma created at Large Hadron Collider. We discuss the implications for signals of quark gluon plasma.

We evaluate the strangeness production from equilibrating and transversely expanding quark-gluon plasma which may be created in the wake of relativistic heavy-ion collisions. We consider boost-invariant longitudinal and cylindrically symmetric transverse expansion of a gluon-dominated partonic plasma, which is in local thermal equilibrium. Initial conditions obtained from the self-screened parton cascade model are used. We empirically find that the final extent of the partonic equilibration rises almost linearly with the square of the initial energy density. This along with the corresponding variation with the number of participants may help us distinguish between various models of parton production.

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We report the first results of the nuclear modification factors and elliptic flow of the φ mesons measured by the PHENIX experiment at RHIC in high luminosity Au+Au collisions at

The evolution and production of strangeness from chemically equilibrating and transversely expanding quark gluon plasma which may be formed in the wake of relativistic heavy ion collisions is studied with initial conditions obtained from the Self Screened Parton Cascade (SSPC) model. The extent of partonic equilibration increases almost linearly with the square of the initial energy density, which can then be scaled with number of participants.

The production of low mass dileptons and soft photons from thermalized Quark Gluon Plasma (QGP) and hadronic matter in relativistic heavy ion collisions is evaluated. A boost invariant longitudinal and cylindrically symmetric transverse expansion of the systems created in central collision of lead nuclei at CERN SPS, BNL RHIC, and CERN LHC, and undergoing a first order phase transition to hadronic matter is considered. A large production of low mass (M < 0.3 GeV) dileptons, and soft photons (pT < 0.4 GeV) is seen to emanate from the bremsstrahlung of quarks and pions. We find an increase by a factor of 2-4 in the low mass dilepton and soft photon yield as we move from SPS to RHIC energies, and an increase by an order of magnitude as we move from SPS to LHC energies. Most of the soft radiations are found to originate from pion driven processes at SPS and RHIC energies, while at the LHC energies the quark and the pion driven processes contribute by a similar amount. The study of the transverse mass distribution is seen to provide interesting details of the evolution. We also find a unique universal behaviour for the ratio of M 2 weighted transverse mass distribution for M = 0.1 GeV to that for M = 0.2 and 0.3 GeV, as a function of MT , for SPS, RHIC, and LHC energies, in the absence of transverse expansion of the system. A deviation from this universal behaviour is seen as a clear indication of the flow. PACS number(s): 12.38. Mh, 13.85.Qk, 25.75.+r