Multiplicity per rapidity in Carruthers and hadron resonance gas approaches

TL;DR

This paper compares two theoretical models, Carruthers and hadron resonance gas, with experimental and simulated data on particle multiplicity per rapidity across a wide energy range, highlighting their respective strengths and limitations.

Contribution

It introduces and applies two approaches to describe rapidity distributions, demonstrating the effectiveness of Carruthers and the limitations of the HRG model across energies.

Findings

Carruthers approach accurately reproduces multiplicity per rapidity across energies.

HRG model describes results well only within a narrower rapidity range.

Carruthers aligns with Gaussian distribution, while HRG needs flow and interaction ingredients.

Abstract

The multiplicity per rapidity of the well-identified particles $\pi^{-}$, $\pi^{+}$, $k^{-}$, $k^{+}$, $\bar{p}$, $p$, and $p-\bar{p}$ measured in different high-energy experiments, at energies ranging from $6.3$ to $5500~$GeV, are successfully compared with the Cosmic Ray Monte Carlo (CRMC) event generator. For these rapidity distributions, we introduce a theoretical approach based on fluctuations and correlations (Carruthers) and another one based on statistical thermal assumptions (hadron resonance gas model). Both approaches are fitted to the two sets of results deduced from experiments and simulations. We found that the Carruthers approach reproduces well the full range of multiplicity per rapidity for all produced particles, at the various energies, while the HRG approach fairly describes the results within a narrower rapidity-range. While the Carruthers approach seems to match well with the Gaussian normal distribution, ingredients such as flow and interactions should be first incorporated in the HRG approach.