Transverse Momentum of Protons, Pions and Kaons in High Multiplicity pp and pA Collisions: Evidence for the Color Glass Condensate?

Understand

The CMS experiment at the Large Hadron Collider has recently presented data on the average transverse momentum of protons, kaons and pions as a function of particle multiplicity.

• We relate the particle multiplicity to saturation momentum using recently published computations of the interaction radius determined from the theory of the Color Glass Condensate.
• We show that the pp and the pA experimental data scale in terms of these saturation momenta.
• Computing transverse momentum spectra for identified particles using Boltzmann-type distributions and relating different associated multiplicities using geometric scaling, these simple distributions reproduce the observed dependence of the mean transverse momentum on particle multiplicities seen in both pp and pA interactions for pions to good accuracy, and to fair agreement for protons and kaons.