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The formulation of the real and virtual photon production rate from strongly interacting matter is presented in the framework of finite temperature field theory. The changes in the hadronic spectral function induced by temperature are discussed within the ambit of the Walecka type model, gauged linear and non-linear sigma models, hidden local symmetry approach, and QCD sum rule approach. The possibility of observing the direct thermal photon and lepton pairs from quark gluon plasma has been contrasted with those from hot hadronic matter with and without medium effects for various mass variation scenarios. At SPS energies, in-medium effects of different magnitude on the hadronic properties for the Walecka model, Brown Rho scaling, and Nambu scaling scenarios are conspicuously visible through the low invariant mass distribution of dileptons and transverse momentum spectra of photons. However, at RHIC energies the thermal photon (dilepton) spectra originating from quark gluon plasma overshines those from hadronic matter for large transverse momentum (invariant mass) irrespective of the models used for evaluating the finite temperature effects on the hadronic properties. It is thus expected that at both RHIC and LHC energies the formation of quark gluon plasma in the initial stages may indeed turn out to be a realistic scenario. Static dilepton spectra. 8.4. Photon and dilepton spectra with space-time evolution. 9. Summary and outlook. Appendix: Thermal propagators.

Ultra-relativistic Heavy-Ion Collision (HIC) generates very strong initial magnetic field ( B) inducing a vorticity in the reaction plane. The high B influences the evolution dynamics that is opposed by the large Faraday current due to electric field generated by the time varying B. We show that the resultant effects entail a significantly large directed flow (v1) of charm quarks (CQs) compared to light quarks due to a combination of several favorable conditions for CQs, mainly: (i) unlike light quarks formation time scale of CQs, τ f ≃ 0.1fm/c is comparable to the time scale when B attains its maximum value and (ii) the kinetic relaxation time of CQs is similar to the QGP lifetime, this helps the CQ to retain the initial kick picked up from the electromagnetic field in the transverse direction. The effect is also odd under charge exchange allowing to distinguish it from the vorticity of the bulk matter due to the initial angular momentum conservation; conjointly thanks to its mass, Mc >> ΛQCD, there should be no mixing with the chiral magnetic dynamics. Hence CQs provide very crucial and independent information on the strength of the magnetic field produced in HIC. 24.85.+p; 05.20.Dd; 12.38.Mh PACS

This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute ‘Heavy Ion Collisions at the LHC—Last Call for Predictions’, held from 14th May to 10th June 2007.

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