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Experimental information on fragment emissions is important in understanding the dynamics of nuclear collisions and in the development of transport model simulating heavy-ion collisions. The composition of complex fragments emitted in the heavy-ion collisions can be explained by statistical models, which assume that thermal equilibrium is achieved at collision energies below 100 MeV/u. Our new experimental data together with theoretical analyses for light particles from Sn+Sn collisions at 270 MeV/u, suggest that the hypothesis of thermal equilibrium breaks down for particles emitted with high transfer momentum. To inspect the system's properties in such limit, the scaling features of the yield ratios of particles from two systems, a neutron-rich system of ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ and a nearly symmetric system of ${}^{108}\mathrm{Sn}+{}^{112}\mathrm{Sn}$, are examined in the framework of the statistical multifragmentation model and the antisymmetrized molecular dynamics model. The isoscaling from low energy particles agree with both models. However the observed breakdown of isoscaling for particles with high transverse momentum cannot be explained by the antisymmetrized molecular dynamics model.

Systematic examination of fusion for $^{39,41,45,47}$K + $^{28}$Si and $^{36,44}$Ar + $^{28}$Si provides insight into the impact of neutron and proton exchange on fusion for nuclei at and near the N=20 and N=28 shells. Comparison of the reduced excitation functions reveals a marked difference between the behavior of open-shell and closed-shell systems. While coupled channels calculations provide a good description for the closed-shell nuclei they significantly under-predict the fusion cross-section for open-shell nuclei. The observed trends are examined in the context of a potential energy surface, including shell effects, and multi-nucleon exchange with consideration of Pauli-blocking., Comment: 7 pages, 4 figures

Heavy ion collisions near the Fermi energy produce a ‘freezout’ region where fragments appear and later decay, emitting mainly neutrons, protons, alpha particles, and gamma rays. These decay products carry information about the decaying nuclei. Fragmentation events may result in high yields of boson particles, especially alpha particles, and may carry important information about the nuclear Bose Einstein condensate (BEC). We study ‘in medium’ four α correlations and link them to the ‘fission’ of 16O in two 8Be in the ground state or 12C*(Hoyle state)+α. Using novel techniques for the correlation functions, we confirm the resonance of 16O at 15.2 MeV excitation energy, and the possibility of a lower resonance, close to 14.72 MeV. The latter resonance is the result of all α particles having 92 keV relative kinetic energies.

The Efimov (Thomas) trimers in excited 12C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64Ni) + 70(64)Zn(64Ni) reactions at the beam energy of E/A = 35 MeV/nucleon. In heavy ion collisions, -particles interact with each other and can form complex systems such as 8Be and 12C. For the 3 -particle systems, multi-resonance processes give rise to excited levels of 12C. The interaction between any two of the 3 -particles provides events with one, two or three 8Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events with the three -particle relative energies consistent with the ground state of 8Be are observed with the decrease of the instrumental error for the reconstructed 7.458 MeV excitation level in 12C, which was suggested as the Efimov (Thomas) state.

The thermodynamics of excited nuclear systems allows one to explore the second-order phase transition in a two-component quantum mixture. Temperatures and densities are derived from quantum fluctuations of fermions. The pressures are determined from the grand partition function of Fisher's model. Critical scaling of observables is found for systems which differ in neutron to proton concentrations thus constraining the equation of state of asymmetric nuclear matter. The derived critical exponent {\beta}= 0.35 \pm 0.01, belongs to the liquid-gas universality class. The critical compressibility factor Pc /{\rho}c Tc increases with increasing neutron number., Comment: 11 pages, 4 figures

The isoscaling and the isobaric yield ratio methods are here analysed with respect to Statistical Multifragmentation Model predictions, to highlight the effects of the secondary decay on the symmetry energy estimation.

Interest in the influence of the neutron-to-proton (N/Z) ratio on multifragmenting nuclei has demanded an improvement in the capabilities of multi-detector arrays as well as the companion analysis methods. The particle identification method used in the NIMROD-ISiS 4 $\pi$ array is described. Performance of the detectors and the analysis method are presented for the reaction of 86Kr+64Ni at 35MeV/u., Comment: Conference procedings

Current advances in technology have enabled dramatic improvements to the performance of multi‐detector arrays within the last 10 years. FAUST is a forward array of 68 Si‐CsI(Tl) detector telescopes that has been in use since 1996. To take full advantage of current technology, FAUST has undergone an overhaul installing new preamplifiers from Zepto Systems and modifications to allow for Dual‐Axis Dual‐Lateral position sensitive detectors to be installed. A new calibration software package has also been developed utilizing a novel linearization algorithm. The combination of these upgrades has led to isotopic identification for elements in the Z = 1–13 range and has greatly increased the angular resolution of the array.

In this work, the isoscaling for the 40Ca+112,124Sn reactions at the beam energy of 45 MeV/A was investigated as a function of the excitation energy of reconstructed quasi‐projectiles. The excitation energy dependence of the isoscaling parameter obtained from the intra‐system isoscaling was investigated and is expected to provide information for the determination of the symmetry energy coefficient of highly excited nuclei.

Simultaneous measurement of both neutrons and charged particles emitted in the reaction {sup 64}Zn + {sup 64}Zn at 45 MeV/nucleon allows comparison of the neutron to proton ratio at midrapidity with that at projectile rapidity. The evolution of N/Z in both rapidity regimes with increasing centrality is examined. For the completely reconstructed midrapidity material one finds that the neutron to proton ratio is above that of the overall {sup 64}Zn + {sup 64}Zn system. In contrast, the reconstructed ratio for the quasiprojectile is below that of the overall system. This difference provides the most complete evidence to date of neutron enrichment of midrapidity nuclear matter at the expense of the quasiprojectile.

Intermediate mass fragment (Z>2) emission in Sn-124,Xe-124+Sn-124,Sn-112 reactions at 28 MeV /nucleon were studied using neutron ion multidetector for reaction oriented dynamics, a 4pi charged particle detection system. A number of observables, such as isotopic yield distributions, energy spectra of light charged particles and intermediate mass fragments, isotopic and isobaric yield ratios, and average neutron to proton ratios are investigated. These observables show significant dependence on the isospin N/Z of the reacting system. It is observed that the formation of neutron-rich clusters are correlated with the excess neutrons in the composite system and depends on the temperature of the emitting source. The origin of light particles and fragments was studied through observations of rapidity distribution as a function of collision violence. With increasing centrality, the heavier He-6 isotope is found to be emitted closer to the midrapidity region than the lighter He-3 isotope. The emission of heavy fragments from the midrapidity region becomes increasingly favorable for fragments with higher charge Z . The results suggest that the midrapidity region is not only neutron rich but also a rich source of heavy fragment (cluster) formation.

Matière Nucléaire NIM; By combining data from a charged particle $^{58}$Ni+$^{58}$Ni experiment at 52 MeV/nucleon with an $^{36}$Ar+$^{58}$Ni experiment at 50 MeV/nucleon for which free neutrons have been detected, an increase in the neutron to proton ratio of the whole nuclear material at midrapidity has been experimentally observed in the reaction $^{58}$Ni+$^{58}$Ni at 52 MeV/nucleon. The neutron-to-proton ratio of the quasi-projectile emission is analyzed for the same reactions and is seen to decrease below the ratio of the initial system. Those observations suggest that an asymmetric exchange of neutrons and protons between the quasiprojectile and the midrapidity region exists.