2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42153Hadron production in leading order pQCD is reviewed. The shape of the single inclusive particle spectra is well described for $p_T \geq 2-3$ GeV at center of mass energies from 20 GeV to 2 TeV. The phenomenological K-factor is found to decrease systematically with $\sqrt{s}$. For ultra-relativistic heavy ion reactions the calculation is augmented with the effects of initial multiple parton scattering and final state radiative energy loss. Baseline CERN-LHC predictions for hadron production in $p+p$ and suppression in central $Pb+Pb$ reactions at $\sqrt{s} = 5.5$ TeV are given in comparison to the corresponding results at BNL-RHIC and CERN-SPS energies.Contribution to the CERN Yellow Report on Hard Probes in Heavy Ion Collisions at the LHC, 10 pages, uses cernrep.clsHigh Energy Physics - PhenomenologyNuclear Theorytext