Karan Singh Vinayak

Effect of density-dependent symmetry energy on nuclear stopping

By using an isospin-dependent quantum molecular dynamics model we study the effect of density-dependent symmetry energy on nuclear stopping. Reactions are carried out for Ca + Ca, Ni + Ni and Sn + Sn for different isotopic compositions. Our aim is to pin down the influence of density-dependent symmetry energy on nuclear stopping. The nuclear stopping is found to decrease with an increase in stiffness of density-dependent symmetry energy. The mild sensitivity of nuclear stopping to different forms of density-dependent symmetry energy is due to the small variation in the density.

Influence of density-dependent symmetry energy on elliptical flow

Abstract.The effect of density-dependent symmetry energy on elliptical flow is studied using the isospin-dependent quantum molecular dynamics model (IQMD). We have used the reduced isospin-dependent cross-section with hard (H) equation of state to study the sensitivity of the elliptical flow to symmetry energy in the energy range 50-1000MeV/nucleon. The elliptical flow becomes zero at a particular energy termed as transition energy. A systematic effort has been made to pin down the transition energy for the density-dependent symmetry energy.

Analyzing density dependent symmetry energy and dynamics for mass-asymmetric heavy-ion reactions

We attempt to study the interplay of density-dependent symmetry energy and its impact on the dynamics evolved in intermediate energy mass-asymmetric reactions. The investigation includes the theoretical analysis of various mass-asymmetric heavy-ion reactions (keeping total mass the same) based on the microscopic isospin-dependent quantum molecular dynamical (IQMD) approach. We present the time evolution, colliding geometry (impact parameter), and excitation energy dependence (100 MeV nucleon−1–1 GeV nucleon−1) of the density and temperature reached during the collisions. The mass-asymmetry factor influences the reaction dynamics drastically at higher incident energies and central collisions. Owing to different density profiles, when subjected to different mass-asymmetry combinations, the role of density-dependent symmetry energy varies accordingly.

Effect of the density dependent symmetry energy on fragmentation

The effect of the density dependence of symmetry energy on fragmentation is studied using isospin-dependent quantum molecular dynamics model(IQMD) Model. We have used the reduced isospin-dependent cross-section with soft equation of state to explain the experimental findings for the system 79Au197 + 79Au197 for the full colliding geometry. In addition to that we have tried to study the collective response of the momentum dependent interactions(MDI) and symmetry energy towards the multifragmentation.

On the role of density-dependent symmetry energy and momentum dependent interactions in multi-fragmentation

We study the multi-fragmentation for the different parameterizations of the density dependent symmetry energy using an isospin-dependent quantum molecular dynamics (IQMD) model. We analyze the sensitivity of fragment production towards various forms of the density dependent symmetry energy. The inclusion of momentum dependent interactions (MDI) results in a larger variation of fragment production. We here highlighted the collective response of the MDI and symmetry energy towards the fragmentation of colliding nuclei at intermediate energies.

The Study of multifragmentation around transition energy in intermediate energy heavy-ion collisions

Fragmentation of light charged particles is studied for various systems at different incident energies between 50 and 1000 MeV/nucleon. We analyze fragment production at the incident energies below, at, and above the transition energies using the isospin-dependent quantum molecular dynamics model. The trends observed for the fragment production and rapidity distributions depend upon the incident energy, size of the fragments, and composite mass of the reacting system, as well as on the impact parameter of the reaction. The free nucleons and light charged particles show continuous homogeneous changes, irrespective of the transition energies, indicating that there is no relation between the transition energy and production of the free as well as light charged particles.

Optimizing the rapidity limit for nuclear stopping in intermediate energy heavy-ion collisions

A systematic study regarding the role of participant matter and spectator matter in nuclear stopping using isospin-dependent quantum molecular dynamics model is presented. The simulations have been carried out with soft equation of state along with the reduced isospin-dependent cross section to study the effect of different types and sizes of rapidity distributions on nuclear stopping for the whole colliding geometry with density-dependent symmetry energy. In addition to that, we attempt to investigate the role of isospin in heavy-ion collisions by calculating the individual contribution of neutrons and protons in nuclear stopping for different systems having different isotopic content.

Impact of momentum dependent equation of state and isospin-dependent cross-section on the neutron-proton Pt-differential elliptic flow

We made a descriptive theoretical analysis for the transverse momentum dependence of elliptic flow (ν2) of neutrons and protons within the framework of isospin-dependent quantum molecular dynamics (IQMD) model. Simulations are carried out for the symmetric reactions of 124Sn+124Sn and 197Au+197Au. We demonstrate the effect of momentum dependent interactions (MDI) as well as of nucleonic cross-sections (isospin-dependent & independent) on the elliptical flow. The MDI and different forms of cross-section are found to affect the elliptical flow of both protons and neutrons considerably.