Gribov Theory of Nuclear Interactions and Particle Densities at Future Heavy-Ion Colliders

TL;DR

This paper applies Gribov reggeon theory and AGK cutting rules to high-energy hadron–nucleus and nucleus–nucleus interactions, deriving inclusive particle spectra and central-rapidity densities that incorporate shadowing from large-mass diffraction. It shows that the Glauber approximation overestimates densities at RHIC and LHC due to additional shadowing, which is constrained by diffractive DIS data and Regge-Gribov dynamics. Quantitatively, shadowing reduces central PbPb densities by about a factor of 3 at the LHC (to ~2500 dn/dy) and about a factor of 2 at RHIC, compared with Monte-Carlo Glauber-based predictions, with a simple factorization dn^{ch}_{AB}/dy ≈ dn^{ch}_{AB,Glaub.}/dy · γ_A γ_B. The results provide a cohesive framework tying soft and hard processes through universal shadowing and offer testable predictions for future heavy-ion collider experiments.

Abstract

Gribov approach to high-energy interactions of hadrons and nuclei is reviewed and applied to calculation of particle production in heavy-ions collisions. It is pointed out that the AGK (Abramovsky, Gribov, Kancheli) cutting rules is a powerful tool to investigate particle spectra in these processes. It leads, in the Glauber approximation, to a simple formula for the density of hadrons produced in the central rapidity region in nucleus-nucleus interactions. An estimate of this density for RHIC and LHC is presented and compared with results of Monte-Carlo calculations. It is shown that the Glauber approximation substantially overestimate particle densities compared to the results of the complete Gribov theory. This is due to extra shadowing in the system, related to large mass diffraction which leads to a strong decrease of particle densities at mid rapidities. Our method of calculation of these effects has been applied to the problem of shadowing of nuclear structure functions and a good agreement with experimental data has been obtained.