[Paper Review] Toward Description of $pp$ and $p{ m C}$ Interactions at High Energies: Problems of Fritiof-based Models

V. Uzhinsky|arXiv (Cornell University)|Apr 8, 2014

High-Energy Particle Collisions Research5 references3 citations

TL;DR

This paper evaluates Fritiof-based models (Fritiof 1.6, Fritiof 7.0, UrQMD 3.3, and HIJING 1.383) in describing high-energy $pp$ and $p{\rm C}$ interactions using NA61/SHINE and NA49 experimental data. It finds that UrQMD fails to reproduce the energy dependence of $\pi^{-}$ production, while Fritiof models underestimate and HIJING overestimates meson yields by ~10%; tuning fragmentation parameters and diffraction cross sections improves agreement, but proton spectra and low-mass diffraction remain poorly described across all models.

ABSTRACT

How do the models (Fritiof 1.6, Fritiof 7.0, UrQMD 3.3 and Hijing 1.383) describe experimental data of NA61/SHINE and NA49 Collaborations on $pp$ and $p{ m C}$ interactions at high energies? An answer on this question is given in the paper. It is shown that the UrQMD model does not reproduce the energy dependence of $π^-$ meson production in $pp$-interactions; the Fritiof 1.6 and the Fritiof 7.0 models underestimate the meson production on $\sim$ 10 %; the Hijing model overestimates the data on $\sim$ 10 %. A change of a LUND fragmentation function parameter in the Fritiof models 1.6/7.0 allows to describe the data. A decreasing of probabilities of binary processes in the UrQMD model like $p+p ightarrow N+N'$ and so on, allows one to describe the data, thus a problem of a correct accounting of the processes arises. An increasing of a probability of the single diffraction dissociation in the Hijing model from 35 % to 50 % allows to describe the data, though a spectrum of masses produced in the diffraction is not satisfactory. A description of the diffraction is a problem in all the models.

Motivation & Objective

• To assess the performance of Fritiof-based models (Fritiof 1.6, Fritiof 7.0, UrQMD 3.3, HIJING 1.383) in describing high-energy $pp$ and $p{\rm C}$ interactions using precise experimental data.
• To identify systematic deficiencies in the simulation of particle production, particularly $\pi^{-}$ and proton rapidity spectra, across these models.
• To investigate the role of single diffraction dissociation and binary interaction cross sections in model discrepancies with data.
• To explore parameter tuning strategies—such as adjusting LUND fragmentation parameters and diffraction probabilities—that improve agreement with experimental spectra.
• To evaluate the impact of intra-nuclear cascading and de-excitation mechanisms on proton spectrum predictions in $p{\rm C}$ interactions.

Proposed method

• Comparison of model predictions (Fritiof 1.6, Fritiof 7.0, UrQMD 3.3, HIJING 1.383) with high-precision NA61/SHINE and NA49 experimental data on $\pi^{-}$, $\pi^{\pm}$, $K^{\pm}$, proton, and antiproton rapidity distributions in $pp$ and $p{\rm C}$ interactions at 20–158 GeV/c.
• Tuning of the LUND fragmentation function parameter in Fritiof models to improve agreement with $\pi^{-}$ production data.
• Adjustment of binary interaction probabilities (e.g., $p+p\rightarrow N+N'$) in UrQMD to reduce overproduction and improve energy dependence.
• Increase of single diffraction dissociation probability in HIJING from 35% to 50% to match data, while assessing the quality of the resulting mass spectrum.
• Implementation of a reggeon theory-inspired model (RTIM) for nuclear de-excitation in tuned Fritiof 1.6 to improve proton spectrum description in $p{\rm C}$ interactions.
• Analysis of $t$-dependence and squared mass distributions in single diffraction to evaluate model performance in low-mass diffraction region.

Experimental results

Research questions

• RQ1 How accurately do Fritiof-based models reproduce the energy dependence of $\pi^{-}$ meson production in $pp$ interactions across 20–158 GeV/c?
• RQ2 Why do UrQMD and Fritiof models fail to describe the $\pi^{-}$ rapidity spectrum, and can tuning the LUND fragmentation parameter resolve this?
• RQ3 To what extent does increasing the single diffraction dissociation cross section in HIJING improve agreement with data, and what are the limitations in the resulting mass spectrum?
• RQ4 Why is the proton spectrum in the target fragmentation region poorly described in all models, and can intra-nuclear cascading and de-excitation mechanisms improve this?
• RQ5 How do model predictions for $p{\rm C}$ interactions compare to data, and does tuning have a significant effect at lower energies?

Key findings

• UrQMD 3.3 fails to reproduce the energy dependence of $\pi^{-}$ production in $pp$ interactions, except at 158 GeV/c, where agreement is coincidental.
• Fritioof 1.6 and Fritiof 7.0 models underestimate $\pi^{-}$ production by approximately 10% across all energies, which is corrected by tuning the LUND fragmentation parameter.
• HIJING 1.383 overestimates $\pi^{-}$ production by ~10%, but agreement improves when the single diffraction dissociation probability is increased from 35% to 50%.
• The tuned Fritiof 1.6 model with de-excitation suppression in intra-nuclear cascades successfully describes the proton spectrum in $p{\rm C}$ interactions, particularly in the target region.
• All models fail to correctly simulate low-mass diffraction dissociation, with poor agreement in $t$-dependence and mass spectrum, indicating a fundamental limitation in current model implementations.
• The inclusion of a reggeon theory-inspired de-excitation model (RTIM) in the tuned Fritiof 1.6 variant improves the description of proton spectra in $p{\rm C}$ interactions, but the central region remains poorly described due to unresolved $pp$ interaction issues.