Cronin effect for protons and pions in pA collisions

TL;DR

This paper investigates the Cronin effect for pions and protons in pA collisions at RHIC energies using a pQCD and color-dipole formalism, highlighting the role of initial-state multiple scatterings and final-state effects.

Contribution

It provides a parameter-free, unified analysis of the Cronin effect for both pions and protons, emphasizing the significance of initial and final-state effects within a color-dipole framework.

Findings

Initial-state multiple scatterings contribute significantly to the Cronin effect.

Final-state effects are important in pA collisions.

Uncertainties in nuclear shadowing and fragmentation functions are discussed.

Abstract

Pions and protons production cross-sections are analyzed in proton-proton and proton-nucleus collisions at the RHIC energy at midrapidity. We employ the pQCD factorization scheme supplemented with the color-dipole formalism to investigate the Cronin effect. We calculate the broadening in the color-dipole approach for different centralities. Our main goal is to investigate, in a parameter-free manner within a unified framework, how much of the cronin effect for both pions and baryons comes from the transverse momentum broadening due to initial partons multi-scatterings. We conclude that final-state effects in pA collisions are important. Uncertainties in nuclear shadowing of various parton distributions and parton fragmentation functions are also discussed.