Spectator partons contribution in the rapidity width of lamda in p+p collisions at various SPS and LHC energies

TL;DR

This study investigates the contribution of spectator partons to the rapidity width of lambda particles in proton-proton collisions across SPS and LHC energies, revealing a universal feature and the role of spectator partons in rapidity distribution broadening.

Contribution

It demonstrates that spectator partons significantly influence the rapidity width of lambda particles in p+p collisions, a phenomenon previously observed mainly in heavy-ion collisions.

Findings

Rapidity width of lambda increases from SPS to LHC energies.

Spectator partons contribute to the broadening of lambda rapidity distribution.

At LHC energies, spectatorless p+p collisions show no non-trivial lambda width contribution.

Abstract

Pseudorapidity distributions of all primary charged particles produced in p+p collisions at various Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies using UrQMD-3.4 and PYTHIA8.2-generated events are estimated and compared with the existing results of UA5 and ALICE collaborations. With both the sets of generated data, the variation of rapidity widths with the rest masses of different mesons and baryons of p+p collisions at various Super Proton Synchrotron (SPS) and LHC energies are presented. An increase in the width of the rapidity distribution of lambda, similar to heavy-ion data, could be seen in p+p collisions as well from SPS to the LHC energies (up to {sqrt_s} =13 TeV) when the entire rapidity space is considered, indicating its universal feature both in p+p and A+A collisions. The genesis of the increased width of rapidity distribution of Lambda in p+p collision is found to be in the production of light flavored quarks and diquarks from the spectator partons of the colliding hadrons resulting {lambda}/{anti_lambda}>1 at the extreme rapidities of the studied p+p collisions. At the LHC energies for central p+p collision, when there is no spectator partons, the rapidity width of {lambda} is found to take the same Gaussian shape as that of lambda and the widths of both the distributions become the same confirming no non-trivial contribution to the rapidity width of {lambda} as seen in heavy-ion and non-central p+p collisions.