Transverse momentum spectra of hadrons in high energy pp and heavy ion collisions

Wepresent a study of transverse momentum (pT) spectra of unidentified charged particles in pp collisions at RHIC and LHC energies from root s = 62.4 GeV to 13 TeV using Tsallis/Hagedorn function. The power law of Tsallis/Hagedorn form gives very good description of the hadron spectra in pT range from 0.2 to 300 GeV/c. The power index n of the pT distributions is found to follow a function of the type a + b/root s with asymptotic value a = 6.8. The parameter T governing the soft bulk contribution to the spectra remains almost same over wide range of collision energies. Wealso provide a Tsallis/Hagedorn fit to the pT spectra of hadrons in pPb and different centralities of PbPb collisions at root s(NN) = 5.02 TeV. The data/fit shows deviations from the Tsallis distribution which become more pronounced as the system size increases. Wesuggest simple modifications in the Tsallis/Hagedorn power law function and show that the above deviations can be attributed to the transverse flow in low p(T) region and to the in-medium energy loss in high pT region.