Eur. Phys. J. Special Topics 229, 3559–3583 (2020)
https://doi.org/10.1140/epjst/e2020-000067-0

Regular Article

Production of light nuclei at colliders – coalescence vs. thermal model

Institute of Physics, Jan Kochanowski University, ul. Uniwersytecka 7, PL-25-406 Kielce, Poland National Centre for Nuclear Research, ul. Pasteura 7, PL-02-093 Warsaw, Poland

^a e-mail: stanislaw.mrowczynski@ncbj.gov.pl

Received: 14 April 2020
Accepted: 27 October 2020
Published online: 21 December 2020

Abstract

The production of light nuclei in relativistic heavy-ion collisions is well described by both the thermal model, where light nuclei are in equilibrium with hadrons of all species present in a fireball, and by the coalescence model, where light nuclei are formed due to final-state interactions after the fireball decays. We present and critically discuss the two models and further on we consider two proposals to falsify one of the models. The first proposal is to measure a yield of exotic nuclide ⁴Li and compare it to that of ⁴He. The ratio of yields of the nuclides is quite different in the thermal and coalescence models. The second proposal is to measure a hadron-deuteron correlation function which carries information whether a deuteron is emitted from a fireball together with all other hadrons, as assumed in the thermal model, or a deuteron is formed only after nucleons are emitted, as in the coalescence model. The p − ³He correlation function is of interest in context of both proposals: it is needed to obtain the yield of ⁴Li which decays into p and ³He, but the correlation function can also tell us about an origin of ³He.