Production of charmed particles in proton-proton and light nucleus-nucleus interactions in Geant4 FTF model

TL;DR

The paper addresses inclusive charm production in proton-proton and light-nucleus collisions using the Geant4 FTF model, motivated by NA61/SHINE preliminary results showing enhanced $D$-meson yields in central Xe+La at 150 GeV/n. It relies on FRITIOF/FTF string fragmentation with the Schwinger mechanism to produce $c\bar{c}$ pairs and calibrates $P_{c\bar{c}}=0.0002$ against data, comparing to QGS and noting that FTF predictions are similar to non-QGP models. The authors provide predictions for ${\rm p+p}$, ${\rm d+d}$, and ${\rm ^4He+^4He}$ at $\sqrt{s_{NN}}=10$ and 20 GeV, aiming to inform SPD experiments. The results reproduce under non-QGP predictions and substantially underestimate the preliminary data, signaling potential enhancement of charm production in nucleus-nucleus collisions possibly related to QGP effects, a question SPD at NICA can address.

Abstract

The total yield of neutral D-mesons (4$π$) in central Xe+La interactions at 150 GeV per nucleon has been calculated within the Geant4 FTF model. Our calculation is close to predictions of Monte Carlo models that do not account for quark-gluon plasma formation. As the predictions, our calculation substantially underestimates preliminary experimental data. The experimental data indicate enhanced charmed particle production in nucleus-nucleus interactions. We present also our calculations for charmed meson production in ${\rm p+p}$, ${\rm d+d}$ and ${\rm ^4He+^4He}$ interactions for future NICA/SPD experiment at $\sqrt{s_{NN}}=$10 and 20 GeV.

Figures (5)

• Figure 1: Preliminary results of the NA61/SHINE collaboration on the 4$\pi$-yield of $D^0$ + $\bar{D}^0$ mesons compared with model predictions. The horizontal shaded band represents the uncertainty of the experimental results due to the unknown phase space distribution of $D^0$ and $\bar{D}^0$. The points with error bars are the experimental data. The horizontal line segments show the model predictions calculated by the collaboration. The red box is the Geant4 FTF model result. "The background in the Monte Carlo (MC) event was described using the EPOS model, while the signal phase space was parametrized using 3 models: AMPT, PHSD and PYTHIA/Angantyr, which predict quite different phase space distributions of open charm." Merzlaya:2024cbt Thus, there are three experimental points.
• Figure 2: Processes of quark and di-quark fragmentations into a charmed meson (a, b) , and fragmentation of a di-quark into a charmed baryon (c).
• Figure 3: Total inclusive cross sections of $D^0$ and $\bar{D}^0$ (a) and $D^+$ and $D^-$ (b) in $pp$ interactions as functions of projectile momenta in the laboratory system. The points are experimental data collected in Lourenco. The curves are our FTF model calculations.
• Figure 4: Properties of charmed hadrons produced in $pp$ interactions at 400 GeV/c. The points are LEBC-EHS collaboration data LEBC-EHS:1988oic. Histograms show our calculations with the FTF model. The QGS model gives analogous results.
• Figure 5: Inclusive distributions of $D$ meson ($D^0$, $\bar{D}^0$, $D^+$ and $D^-$) in ${\rm p+p}$, ${\rm d+d}$ and $^4{\rm He}+^4{\rm He}$ interactions. The upper histograms correspond to $^4{\rm He}+^4{\rm He}$ interactions. The low histogram are for ${\rm p+p}$ ones. The middle histograms are for ${\rm d+d}$ interactions. The upper figures (a, b) are for $\sqrt{s}=10$ GeV, the low figures (c, d) are for $\sqrt{s}=20$ GeV