Multifragmentation of reconstructed quasi-projectiles in the mass region A ∼ 30

Abstract

The production of fragments from a broad range of reconstructed quasiprojectiles obtained in the interaction of 32 S (45 MeV/nucleon) with 112 Sn was studied. A good description of the experimental data on the multifragmentation of these light quasi-projectiles with a model framework based on deep inelastic transfer followed by SMM (statistical multifragmentation model) was obtained. The charge and mass distributions of the observed fragments show that the break-up of a given quasi-projectile source is highly correlated to its isospin composition. The sensitivity of the hot primary fragments to the symmetry energy was investigated in detail. It was found that for the present light systems (A∼30), a good description of the experimental data on the charge distributions, the N/Z distributions and the isotopic distributions of the fragments is obtained by the SMM calculations involving the standard (C sym = 25 MeV), as well as, a reduced value of the symmetry energy (C sym = 8 MeV). However, the reduced value of the symmetry energy appears to provide a better description of the isotopic distributions in most of the cases. This is in agreement with an overall reduction of the symmetry energy of primary fragments indicated by a number of multifragmentation studies of heavier systems.

Evaluation of the hyperon binding energy via statistical production of hypernuclei

“…In this case it would be instructive to select the reaction conditions leading to similar freeze-out states. The freeze-out restoration methods were extensively tested previously: In particular, the masses and excitation energies of the hypernuclear residues can be found with a sufficient precision [40,41]. One can analyze the subsequent ranges of the excitation energy (from low to very high ones) to investigate the evolution of the hypernuclei with the temperature and the phase transition in hyper-matter.…”

Quantum suppression of fluctuations and temperatures of reconstructedA∼ 30 quasi-projectiles

“…Because of the thickness of the silicon, the charged particles collected are, by design, heavily biased toward fragments produced from the decay of the hot QP, i.e. the projectile-like remnant originating in peripheral and mid-peripheral collisions [45,46]. Particles were identified in both atomic number (Z) and mass number (A) for up to at least Z = 8 throughout the array and up to Z = 13 for several detectors.…”

“…We note that in the Fermi energy range (i.e., 20-50 MeV/nucleon), the hot QPs are produced in peripheral and semiperipheral collisions of the projectile with the target following intense exchange of nucleons during their contact time. This mechanism leads to QPs with a broad distribution in N/Z and excitation energy [21,45,46]. In the present work, QPs were reconstructed on an event-by-event basis with two constraints.…”

“…First, in each event, the sum of the charge of the detected particles was required to be equal to the charge of the beam (Z = 16). This condition has previously been shown to select for events with properties indicative of a QP [45,46]. Second, the sum of the mass of the detected particles was required to be equal to the mass of the beam (A = 32).…”

Intermediate Mass Fragment Emission in ${^{32}}$S +${^{51}}$V, ${^{109}}$Ag, and ${^{238}}$U Collisions at E~=~31.6~MeV~A

“…properties of neutron stars. Because of this important connection a lot of recent studies deal with the symmetry energy in fragmentation reactions [20], [21], [22], [23], [24]. Other work concentrates more on the target N/Z dependence [25], [26], [27].…”