Breakup Temperature of Target Spectators in Au + Au Collisions at E/A = 1000 MeV

Breakup temperatures were deduced from double ratios of isotope yields for target spectators produced in the reaction Au + Au at 1000 MeV per nucleon. Pairs of $^{3,4}$He and $^{6,7}$Li isotopes and pairs of $^{3,4}$He and H isotopes (p, d and d, t) yield consistent temperatures after feeding corrections, based on the quantum statistical model, are applied. The temperatures rise with decreasing impact parameter from 4 MeV for peripheral to about 10 MeV for the most central collisions. The good agreement with the breakup temperatures measured previously for projectile spectators at an incident energy of 600 MeV per nucleon confirms the observed universality of the spectator decay at relativistic bombarding energies. The measured temperatures also agree with the breakup temperatures predicted by the statistical multifragmentation model. For these calculations a relation between the initial excitation energy and mass was derived which gives good simultaneous agreement for the fragment charge correlations. The energy spectra of light charged particles, measured at $\theta_{lab}$ = 150$^{\circ}$, exhibit Maxwellian shapes with inverse slope parameters much higher than the breakup temperatures. The statistical multifragmentation model, because Coulomb repulsion and sequential decay processes are included, yields light-particle spectra with inverse slope parameters higher than the breakup temperatures but considerably below the measured values. The systematic behavior of the differences suggests that they are caused by light-charged-particle emission prior to the final breakup stage. PACS numbers: 25.70.Mn, 25.70.Pq, 25.75.-qComment: 29 pages, TeX with 11 included figures; Revised version accepted for publication in Z. Phys. A Two additional figure

Liquid-gas phase transition in nuclear multifragmentation

The equation of state of nuclear matter suggests that at suitable beam energies the disassembling hot system formed in heavy ion collisions will pass through a liquid-gas coexistence region. Searching for the signatures of the phase transition has been a very important focal point of experimental endeavours in heavy ion collisions, in the last fifteen years. Simultaneously theoretical models have been developed to provide information about the equation of state and reaction mechanisms consistent with the experimental observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos corrected, minor text change

Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10

Production of hypernuclei and properties of hyper-nuclear matter

The relativistic nucleus-nucleus collisions can produce hypernuclei and low-temperature hyper-matter as a result of hyperon capture by nuclear residues and free nucleons. We use the transport, coalescence and statistical models to describe the whole process, and point at the important advantages of such reactions: A broad variety of formed hypernuclei in masses and isospin allows for investigating properties of exotic hypernuclei, as well as the hypermatter both at high and low temperatures. The abundant production of multi-strange nuclei that can give an access to multi-hyperon systems and strange nuclear matter. The de-excitation of hot hyper-cluster will allow for the hyperon correlation studies. There is a saturation of the hypernuclei production at high energies, therefore, the optimal way to pursue this experimental study is to use the accelerator facilities of intermediate energies.Comment: 3 figures, 4 pages, in Proceedings of The 18th International Conference on Strangeness in Quark Matter (SQM 2019), 10-15 June 2019, Bari, ITAL

Nuclear fragmentation and critical temperature for the liquid-gas phase transition region

18th International Nuclear Physics Divisional Conference of the European-Physical-Society -- AUG 23-29, 2004 -- Prague, CZECH REPUBLICWe have investigated the evolution of fragment mass and charge distributions for Au-197, Sn-124 and La-124 nuclei, in the excitation energy range 2 - 12 MeV/nucleon. It is seen that isospin of a nucleus and critical temperature of nuclear matter is highly effective on the multifragmentation phenomena in the phase transition region of finite nuclei

Thermal and dynamic multifragmentation of hot nuclei similarities and differences

The experimental data on fragment multiplicities, their energy and charge distributions, the emission times are considered for the nuclear multifragmentation process induced by relativistic light projectiles (protons, helium) and heavy ions. With light projectiles, the multifragmentation is a pure "thermal" process, well described by the statistical models. Heavy-ion-induced multifragmentation is influenced by dynamic effects related first of all to the compression of the system in the collision. But statistical models can also be applied to rendering the partition of the system if the excitation energy is less than 10 MeV/nucleon and compression is modest. For the central collision of heavy ions the statistical approach fails to describe the data

Phase transitions in highly excited nuclei

Phase transition in highly excited nucleus is treated in terms of thermo-dynamics of microensembles. The emission of intermediate mass fragments from pure thermally excited heavy nucleus 197Au is an indication of the liquid to fog phase transition. Evidence of the spinodal decomposition of the heavy nuclear system is found and its relation to the multisaddle transition configuration and freeze-out state is presented

Phase transitions in highly excited nuclei

Phase transition in highly excited nucleus is treated in terms of thermo-dynamics of microensembles. The emission of intermediate mass fragments from pure thermally excited heavy nucleus Au is an indication of the liquid to fog phase transition. Evidence of the spinodal decomposition of the heavy nuclear system is found and its relation to the multisaddle transition configuration and freeze-out state is presented. 19

Dynamical. and statistical fragment emission properties in 200 A MeV Ne-20+Ar-40 collisions

Dynamical and statistical fragment emission processes in 200 A MeV Ne-20 + Ar-40 collisions are well probed by measurements of charge (Z), mass (A) and momentum vector ((p) over right arrow) of all fragments in large parts of the available momentum space. We present such data obtained at the cluster-jet target of the CELSIUS storage ring, for the first time with an internal, ultra-high vacuum (UHV) compatible detector system (CHICSi). Energy and angular dependence in Z and A distributions are not reproduced by a single-step model, e.g., those based on molecular dynamics (MD), but require a complete three-step model. We use here the intranuclear cascade+ statistical multifragmentation + secondary evaporation model (CFEM). The angular dependence of isobaric ratios, like He-6/Li-6 at low emission velocities and temperatures extracted from isotopic (double) ratios, do exhibit differences, even from this model. These differences, which call for adjustment of model parameters, are discussed. (c) 2005 Elsevier B.V. All rights reserved