On saturation of charged hadron production in pp collisions at LHC

Abstract

First results on charged hadron transverse momentum spectra in pp collisions obtained by the CMS Collaboration at LHC were analyzed in z-scaling approach. The first LHC data confirm z-scaling. The saturation regime of the scaling function psi(z) observed in pp and antp-pp interactions at lower energy sqrt s = 19-1960 GeV is verified. The saturation of psi(z) for charged hadrons is found down to z=0.05 at the highest energy sqrt s = 2360 GeV reached till now at colliders. A microscopic scenario of hadron production is discussed in connection with search for new signatures of phase transitions in hadron matter. Constituent energy loss and its dependencies on the transverse momentum of charged hadrons and collision energy are estimated. The beam energy scan at LHC in the saturation region is suggested.