Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions

K. A. Bugaev; O. V. Vitiuk; B. E. Grinyuk; V. V. Sagun; N. S. Yakovenko; O. I. Ivanytskyi; G. M. Zinovjev; D. B. Blaschke; E. G. Nikonov; L. V. Bravina; E. E. Zabrodin; S. Kabana; S. V. Kuleshov; G. R. Farrar; E. S. Zherebtsova; A. V. Taranenko

doi:10.1140/epja/s10050-020-00296-5

2024 Impact factor 2.8

Hadrons and Nuclei

Theory of Hot Matter and Relativistic Heavy-Ion Collisions (THOR)

Eur. Phys. J. A (2020) 56: 293
https://doi.org/10.1140/epja/s10050-020-00296-5

Regular Article – Theoretical Physics

Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions

K. A. Bugaev¹^,2^a, O. V. Vitiuk²^,3, B. E. Grinyuk¹, V. V. Sagun¹^,4, N. S. Yakovenko², O. I. Ivanytskyi¹^,4, G. M. Zinovjev¹, D. B. Blaschke⁵^,6^,7, E. G. Nikonov⁸, L. V. Bravina³, E. E. Zabrodin³^,9, S. Kabana¹⁰, S. V. Kuleshov¹¹, G. R. Farrar¹², E. S. Zherebtsova⁷^,13 and A. V. Taranenko⁷

¹ Bogolyubov Institute for Theoretical Physics, Metrologichna str. 14B, 03680, Kyiv, Ukraine
² Department of Physics, Taras Shevchenko National University of Kyiv, 03022, Kyiv, Ukraine
³ University of Oslo, POB 1048 Blindern, 0316, Oslo, Norway
⁴ Department of Physics, CFisUC, University of Coimbra, 3004-516, Coimbra, Portugal
⁵ Institute of Theoretical Physics, University of Wroclaw, Max Born Pl. 9, 50-204, Wroclaw, Poland
⁶ Bogoliubov Laboratory of Theoretical Physics, JINR Dubna, Joliot-Curie Str. 6, 141980, Dubna, Russia
⁷ National Research Nuclear University (MEPhI), Kashirskoe Shosse 31, 115409, Moscow, Russia
⁸ Laboratory for Information Technologies, Joint Institute for Nuclear Research, 141980, Dubna, Russia
⁹ Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119899, Moscow, Russia
¹⁰ Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica, Chile
¹¹ Departamento de Ciencias Físicas, Universidad Andres Bello, Sazié 2212, Piso 7, Santiago, Chile
¹² Department of Physics, New York University, 10003, New York, NY, USA
¹³ Institute for Nuclear Research, Russian Academy of Science, 108840, Moscow, Russia

^a bugaev@th.physik.uni-frankfurt.de

Received: 21 May 2020
Accepted: 30 October 2020
Published online: 20 November 2020

Abstract

Here we develop a new strategy to analyze the chemical freeze-out of light (anti)nuclei produced in high energy collisions of heavy atomic nuclei within an advanced version of the hadron resonance gas model. It is based on two different, but complementary approaches to model the hard-core repulsion between the light nuclei and hadrons. The first approach is based on an approximate treatment of the equivalent hard-core radius of a roomy nuclear cluster and pions, while the second approach is rigorously derived here using a self-consistent treatment of classical excluded volumes of light (anti)nuclei and hadrons. By construction, in a hadronic medium dominated by pions, both approaches should give the same results. Employing this strategy to the analysis of hadronic and light (anti)nuclei multiplicities measured by ALICE at $\sqrt{s_{NN}} = 2.76$ $\sqrt{s_{NN}} =2.76$ TeV and by STAR at $\sqrt{s_{NN}} = 200$ $\sqrt{s_{NN}} =200$ GeV, we got rid of the existing ambiguity in the description of light (anti)nuclei data and determined the chemical freeze-out parameters of nuclei with high accuracy and confidence. At ALICE energy the nuclei are frozen prior to the hadrons at the temperature $T = 175 . 1_{- 3.9}^{+ 2.3}$ $T = 175.1^{+2.3}_{-3.9}$ MeV, while at STAR energy there is a single freeze-out of hadrons and nuclei at the temperature $T = 167.2 \pm 3.9$ $T = 167.2 \pm 3.9$ MeV. We argue that the found chemical freeze-out volumes of nuclei can be considered as the volumes of quark-gluon bags that produce the nuclei at the moment of hadronization.