Strong longitudinal color field effects in pp collisions at energies available at the Large Hadron Collider

TL;DR

This paper investigates the impact of strong longitudinal color fields in proton-proton collisions at LHC energies using an energy-dependent string tension model, successfully explaining various multiparticle observables and predicting enhanced baryon ratios.

Contribution

It introduces an energy-dependent string tension in the HIJING model to describe color field effects, aligning well with experimental data and offering predictions for future collider energies.

Findings

Reproduces energy dependence of multiparticle observables from RHIC to LHC.

Predicts significant enhancement of baryon-to-meson ratios at LHC energies.

Shows the effective string tension increases with energy, influencing particle production.

Abstract

We study the effect of strong longitudinal color fields (SCF) in p+p reactions up to Large Hadron Collider energies in the framework of the HIJING/BBbar v2.0 model that combines (collinear factorized) pQCD multiple minijet production with soft longitudinal string excitation and hadronization. The default vacuum string tension, kappa0 = 1 GeV/fm, is replaced by an effective power law energy dependent string tension, that increases monotonically with center-of-mass energy. The exponent 0.06 is found sufficient to reproduce well the energy dependence of multiparticle observables in RHIC, Tevatron, as well as recent LHC data. This exponent is found to be only half of that predicted by the Color Glass Saturation model, lambda(CGC)=0.115, where gluon fusion multiparticle production mechanisms are assumed. In HIJING/BBbar v2.0, the rapid growth of central-rapidity density with energy is due to the interplay of copious minijet production and increasing SCF contributions. The large (strange)baryon-to-meson ratios measured at Tevatron energies are well described. A significant enhancement of these ratios is predicted up to the highest LHC energy (14 TeV). The effect of JJbar loops and SCF on baryon-anti-baryon asymmetry and its relation to baryon number transport is also discussed.