Correlations with projectile-like fragments and emission order of light charged particles

Abstract

Correlations of midrapidity light charged particles (LCPs) and intermediate mass fragments (IMFs) with projectile-like fragments (PLFs) have been examined from the 35 MeV/u 70 Zn + 70 Zn, 64 Zn + 64 Zn, and 64 Ni + 64 Ni reaction systems. A new method was developed to examine the flow of the particles with respect to the PLF. The invariant PLF-scaled flow allowed for the dynamics of the midrapidity Z = 1-4 particles to be studied. Strong differences in the PLF-scaled flow were observed between the different isotopes. In particular, the most n-rich LCPs exhibited a negative PLF-scaled flow in comparison to the other LCPs. A classical molecular dynamics model and a three-body Coulomb trajectory simulation were both used to show that the PLF-scaled flow observable could be connected to the average order of emission of the LCPs. The experimental results suggest that the midrapidity region is preferentially populated with neutron-rich LCPs and Z = 3-4 IMFs at a relatively early stage in the collision. The deuteron and 3 He particles are emitted later followed, lastly, by protons and alphas. The average order of emission of the midrapidity LCPs was extracted from the constrained molecular dynamics simulations and showed good agreement with the emission order suggested by the experimental PLF-scaled flow results.

Experimental effects of dynamics and thermodynamics in nuclear reactions on the symmetry energy as seen by the CHIMERA 4 $ \pi$ detector

“…Adopting this interpretation, much effort is devoted nowadays to determine the density evolution of the midrapidity source [42]. On the other hand light charged particles and IMFs emitted at mid-rapidity can be produced by different reaction mechanisms with different chronology, like pre-equilibrium emission from deformed PLF and TLF nuclei or sequential emission in a later stage of the reaction [43,44,45,46], as a result of a delicate competition between one body dissipation mechanism and two body in medium interaction.…”

“…Notice that this behavior is apparently quite different from the results of the mean-field approach (SMF) described above in this section [128], that anyway is related to different reactions. The necessity to compare predictions on symmetry energy observables as obtained by different models of the transport dynamics is a key issues of the nowadays comparison between theory and experimental data [43,131,132].…”

The equation of state and symmetry energy of low-density nuclear matter

“…Another experiment [46,47] was performed to study the dependence of the thermodynamic properties of nuclear material on neutron-proton asymmetry [48]. Here, collisions of 70 Zn+ 70 Zn, 64 Zn+ 64 Zn, and 64 Ni+ 64 Ni at E/A = 35 MeV were studied.…”

Triple α -particle resonances in the decay of hot nuclear systems *

“…A detailed description of the experiment can be found in Refs. [14][15][16]. When two heavy ions at 35 MeV/nucleon collide, the excitation energy deposited in the system is large enough for the system to get gently compressed at the beginning and then it expands and enters an instability region, the spinodal region, similar to the liquid-gas (LG) phase transition [17][18][19][20][21].…”