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.

The ratio of transverse momentum distribution of thermal photons to dilepton has been evaluated. It is observed that this ratio reaches a plateau beyond a certain value of transverse momentum. We argue that this ratio can be used to estimate the initial temperature of the system by selecting the transverse momentum and invariance mass windows judiciously. It is demonstrated that if the radial flow is large then the plateau disappear and hence a deviation from the plateau can be used as an indicator of large radial flow. The sensitivity of the results on various input parameters has been studied.

The transverse momentum distribution of the direct photons measured by the PHENIX collaboration in Au + Au collisions at √ s N N = 200 GeV/A has been analyzed. It has been shown that the data can be reproduced reasonably well assuming a deconfined state of thermalized quarks and gluons with initial temperature more than the transition temperature for deconfinement inferred from lattice QCD. The value of the initial temperature depends on the equation of state of the evolving matter. The sensitivities of the results on various input parameters have been studied. The effects of the modifications of hadronic properties at non-zero temperature have been discussed.

We analyze the measured spectra of π ± , K ± , p(p) in pp collisions at √ s = 0.9, 2.76 and 7 TeV, in the light of blast-wave model to extract the transverse radial flow velocity and kinetic temperature at freeze-out for the system formed in pp collisions. The dependency of the blast-wave parameters on average charged particle multiplicity of event sample or the 'centrality' of collisions has been studied and compared with results of similar analysis in nucleus-nucleus (AA) and proton-nucleus (pA) collisions. We analyze the spectra of K 0 s , Λ(Λ) and Ξ − also to see the dependence of blast-wave description on the species of produced particles. Within the framework of the blast-wave model, the study reveals indication of collective behavior for high-multiplicity events in pp collisions at LHC. Strong transverse radial flow in high multiplicity pp collisions and its comparison with that in pA and AA collisions match with predictions from a very recent theoretical work [Shuryak and Zahed 2013 arXiv:hep-ph/1301.4470] that addresses the conditions for applicability of hydrodynamics in pp and pA collisions.

A microscopic approach has been employed to study the kaon productions in heavy ion collisions. The momentum integrated Boltzmann equation has been used to study the evolution of strangeness in the system formed in heavy ion collision at relativistic energies. The kaon productions have been calculated for different centre of mass energies ( √ sNN) ranging from AGS to RHIC. The results have been compared with available experimental data. We obtain a non-monotonic horn like structure for K + /π + when plotted with √ sNN with the assumption of an initial partonic phase beyond a certain threshold in √ sNN . However, a monotonic rise of K + /π + is observed when a hadronic initial state is assumed for all √ sNN. Experimental values of K − /π − are also reproduced within the ambit of the same formalism. Results from scenarios where the strange quarks and hadrons are formed in equilibrium and evolves with and without secondary productions have also been presented.PACS numbers: 25.75.Dw,24.85.+p