Light cluster production at NICA

Abstract

In a recent publication [1] the importance of measuaring light clusters at future NICA and FAIR experiments as "rare probes" for in-medium characteristics was presented. Within theoretical conciderations is shown how clusters would be affected by medium affects as given collider energies. PACS numbers: 25.75.-q Relativistic heavy-ion collisions 21.65.-f Nuclear Matter 21.60.Gx Cluster models 05.30.-d Quantum statistical mechanicsTo decide on characteristics of the matter produced in energetic nuclear collisions a variety of probes is needed that provide different perspectives. One class of such probes are nuclear clusters. Here we discuss the insights that the clusters can provide within the NICA program, both within fixed target and collider setups, at BM@N and MPD, respectively.To provide a general background we show in Fig. 1 a phase diagram of dense nuclear matter including lines for Mott dissociation of deuterons (d), tritons (t) and alpha particles (α), taken from [2], see also [3], together with the parametrization of the chemical freeze-out line [4] from statistical model fits of hadron production in heavy-ion collisions. Several laboratory energies from the energy range accessible at the NICA accelerator complex are shown as labeled dots on that line.For the sake of generating the illustration, the hadronic phase is described by a DD2 equation of state [5] with a liquid-gas phase transition (blue line with critical endpoint), extended by adding components of the hadron resonance gas, in particular pions and kaons. The quark-gluon matter phase for the figure is described by a PNJL model exhibiting a first * Presented at Critical Point and Onset of Deconfinement 2016, Wroc law (1) arXiv:1711.05631v1 [nucl-th]

Light nuclei production as a probe of the QCD phase diagram

“…Although our results cannot tell whether the phase transition is due to deconfinement or the restoration of chiral symmetry, they provide a complementary evidence for the occurrence of a first-order phase transition and a critical endpoint in the QCD phase diagram to those that have been suggested in the literatures. These include the irregularities of the trace anomaly ( − 3p)/T 4 and quasi-plateaus of entropy per baryon [10] at two ranges of the center-of-mass collision energies of √ s N N = 3.8 − 4.9 GeV and √ s N N = 7.6 − 9.2 GeV, based on the non-smooth chemical freeze-out analysis [50]; the explanation of the collision energy dependence of the K + /π + ratio in terms of the chiral symmetry restoration [51]; large higher-order moments in the event-by-event fluctuations of conserved charges [9]; enhanced dilepton production [16,52]; and the need of deconfinement in describing measured rapidity distribution [30] and direct flow [24,30] of light nuclei. To verify the present conclusion, it will be particularly important to carry out similar studies using microscopic transport model simulations as well as hydrodynamics calculations with the proper treatment of the equation of state and the critical fluctuations.…”

Towards a Unified Quark-Hadron-Matter Equation of State for Applications in Astrophysics and Heavy-Ion Collisions

“…Kinetic codes based on a single-particle description, but also QMD and AMD codes which simulate cluster formation using the coalescence model and simpler concepts, have to be improved to obtain a microscopic description of cluster formation. Work in this direction is in progress [14,116,117]. Alternatively, the freeze-out concept has been used to model the expansion process of the "fireball".…”

Composition of Nuclear Matter with Light Clusters and Bose–Einstein Condensation of $$\alpha $$ α Particles

“…The topics of current interest are, for example, the improvements on the supernova and warm neutron star equations of state and thermodynamics [7,8] which include the multi-cluster composition of matter [9,10,11,12,13,14,15,16,17,18,19,20,21]. Another aspect of the problem is the effects of light clusters in intermediate energy heavy ion collisions [22,23,24,25,26,27] which were extensively studied using various methods, see for example [28,29,30]. Furthermore, the general many-body problem of bound state formation in nuclear medium is an outstanding problem on its own right [31,32,33,34,35,36,37,38,39,40,41,42].…”