Hard scattering cross sections at LHC in the Glauber approach: from pp to pA and AA collisions

Abstract

The scaling rules of the invariant yields and cross sections for hard scattering processes in proton-nucleus ($pA$) and nucleus-nucleus ($AB$) reactions at LHC energies relative to those of nucleon-nucleon $NN$ (isospin averaged $pp$) collisions are reviewed within the Glauber geometrical formalism. The number of binary inelastic collisions for different centrality classes in p+Pb and Pb+Pb collisions at $\sqrt{s_{NN}}$ = 8.8 TeV and 5.5 TeV respectively, as obtained from a Glauber Monte Carlo, are also given.

Contribution to the CERN Yellow Report on Hard Probes in Heavy Ion Collisions at the LHC. [Wrong numerical examples of scaling of AA cross-sections from pp values for different centralities have been corrected: Eqs. (29)-(30) and Eqs. (35)-(40)]