Elliptical flow and isospin effects in heavy-ion collisions at intermediate energies

Abstract

The elliptical flow of fragments is studied for different systems at incident energies between 50 and 1000 MeV/nucleon using the isospin-dependent quantum molecular dynamics (IQMD) model. Our findings reveal that elliptical flow shows a transition from positive (in-plane) to negative (out-of-plane) values in the midrapidity region at a certain incident energy known as the transition energy. This transition energy is found to depend on the model ingredients, size of the fragments, and composite mass of the reacting system as well as on the impact parameter of the reaction. A reasonable agreement is observed for the excitation function of elliptical flow between the data and our calculations. Interestingly, the transition energy is found to exhibit a power-law mass dependence.

Examining the effect of a binding-energy-dependent clusterization algorithm on isospin-sensitive observables in heavy-ion collisions

“…In addition, UrQMD, in which meson production and nucleon resonances are well treated, has been able to explain the experimental data above 1 GeV/nucleon also, where IQMD model fails badly. For 3 H/ 3 He, the zig zag behavior with incident energy is due to the platue formation for LCPs production around 400 MeV/nucleon [36]. The sensitivity of n/p ( 3 H/ 3 He) with MSTB is decreasing (increasing) towards the high incident energy, which is quite interesting observation.…”

On the momentum distribution of particles participating in nuclear stopping

“…Recently, Zhang et al [6] pointed out that the stopping observables depend strongly on the N-N cross-section and mean field, whereas the flow observables depend comparatively on the uncertainties in the N-N cross-section and mean field. Kumar et al studied the effect of different EoS and N-N cross-section on nuclear stopping and found it to be highly sensitive towards the N-N cross-section and weakly towards different EoS [7,8]. Despite these observations, there are further ambiguities associated with the nuclear EoS.…”

Rapidity distribution as a probe for elliptical flow at intermediate energies

“…Using directed flow, the balance energy has also been calculated in the literature (but over the entire rapidity distribution) [24][25][26][27][28][29][30][31][32]. The rapidity distribution affects many phenomena in the intermediate-energy region, such as particle production, nuclear stopping [3][4][5][6][7][8][9][10], and now the elliptical flow. The transition energy increases in the rapidity region between |Y | 0 1 and |Y | 1 5.…”

“…The inset in the figure clearly shows the change in behavior around −1 25, which is also true for the other side. The rapidity distribution is also often used as the thermalization source in the literature [3][4][5][6][7][8][9][10]. On this basis, we have divided the rapidity distribution into five different zones, of which three include |Y | < 0 1 (participant zone), while other two exclude this region (target and projectile spectator).…”

“…The interest in low energies, however, is for isospin effects in fusion processes [1][2][3][4][5][6][7][8][9][10]. These investigations have been performed with the help of rare phenomena, such as multifragmentation, collective flow, particle production as well as nuclear stopping [33][34][35][36][37][38][39][40][41].…”