Role of net baryon density on rapidity width of identified particles from the lowest energies available at the CERN Super Proton Synchrotron to those at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

TL;DR

This study investigates how net baryon density influences the rapidity width of identified particles across a wide energy range from SPS to LHC, revealing universal patterns and challenging existing particle production models.

Contribution

It demonstrates the persistent jump in rapidity width versus rest mass at high energies and suggests pair production isn't the sole mechanism at LHC energies.

Findings

Rapidity width of $\\Lambda$ increases with energy.

Universal jump in rapidity width versus mass from SPS to LHC.

Separate mass scaling for mesons and baryons persists at LHC.

Abstract

Widths of the rapidity distributions of various identified hadrons generated with the UrQMD-3.4 event generator at all the Super Proton Synchrotron (SPS) energies have been presented and compared with the existing experimental results. An increase in the width of the rapidity distribution of $\Lambda$ could be seen with both Monte Carlo (MC) and experimental data for the studied energies. Using MC data, the study has been extended to Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies. A similar jump, as observed in the plot of rapidity width versus rest mass at Alternating Gradient Synchrotron (AGS) and all SPS energies, persists even at RHIC and LHC energies, confirming its universal nature from AGS to the highest LHC energies. Such observation indicates that pair production may not be the only mechanism of particle production at the highest LHC energies. However, with MC data, the separate mass scaling for mesons and baryons is found to exist even at the top LHC energy.