Forward hadron production in pp collisions at LHC energies from an event generator based on the color glass condensate framework

TL;DR

This study uses a CGC-inspired Monte Carlo event generator to analyze forward hadron production in high-energy pp collisions at LHC, comparing models and frameworks to experimental data.

Contribution

It systematically evaluates different initial conditions for the rcBK evolution and compares dilute-dense and dense-dense frameworks against LHCb data.

Findings

Current LHCb data favor MV$^eta$ and MV$^e$ models.

k_T factorization better describes mid-rapidity spectra than DHJ.

Differences among models grow at higher transverse momentum and mid-rapidity.

Abstract

We investigate inclusive forward single-hadron production in high-energy proton--proton collisions using a CGC-inspired Monte Carlo event generator, MC-CGC. We carried out a systematic study of the sensitivity of the running-coupling Balitsky-Kovchegov (rcBK) evolution equation to its initial conditions by comparing three parameterizations: the McLerran-Venugopalan (MV) model and its two HERA DIS-constrained variants, MV$^\gamma$ and MV$^e$. Our results indicate that the current LHCb data favor the MV$^\gamma$ and MV$^e$ models, while the differences from the original MV model become more pronounced at higher transverse momentum and at mid-rapidity. As a complementary analysis, we also compared the dilute-dense (DHJ factorization) and dense-dense ($k_T$ factorization) frameworks. We found that the $k_T$ factorization framework provides a better description of the particle production spectra at mid-rapidity than the DHJ framework, where both the projectile and target are in the dense regime at LHC energies. Predictions for the FoCal measurements at ALICE, including the production of identified neutral mesons and jets, are also presented.