Dmytro Oliinychenko, Long-Gang Pang, Hannah Elfner, and Volker Koch, Microscopic study of deuteron production in PbPb collisions at √s=2.76TeV via hydrodynamics and a hadronic afterburner,  Phys. Rev. C 99, 044907 (2019)

The deuteron yield in Pb+Pb collisions at √s_NN=2.76 TeV is consistent with thermal production at a freeze out temperature of T=155 MeV. The existence of deuterons with binding energy of 2.2 MeV at this temperature was described as “snowballs in hell” [P. Braun-Münzinger, B. Dönigus, and N. Löher, CERN Courier, August 2015]. We provide a microscopic explanation of this phenomenon, utilizing relativistic hydrodynamics and switching to a hadronic afterburner at the above-mentioned temperature of T=155 MeV. The measured deuteron p_T spectra and coalescence parameter B₂(p_T) are reproduced without free parameters, only by implementing experimentally known cross sections of deuteron reactions with hadrons, most importantly πd↔πnp.

Figure: deuteron yield (both in hydrodynamics and afterburner) versus time for the scenarios, described in the text. Bottom: relative amount of energy in the afterburner. This is to indicate, how much of the system is already treated by the afterburner. 

Further readings: APS Physics, DOE NP Highlights