Mass asymmetry effects on multifragmentation.
Nuclear dynamics of mass asymmetric systems at balance energy.
Study of stability of nuclei, flow and multifragmentation in heavy-ion collisions.
Mass asymmetry effects on geometry of vanishing flow.
Onset of multifragmentation and vaporization in Au-Au collisions
Using the quantum molecular dynamics model, we study the nuclear dynamics at the balance energy of mass asymmetric colliding nuclei by keeping the total mass of the system fixed as 40, 80, 160, and 240. The calculations are performed by varying the m
ass asymmetry ($eta$ = $frac{A_{T}-A_{P}}{A_{T}+A_{P}}$; where $A_{T}$ and $A_{P}$ are the masses of the target and projectile, respectively) of the reaction from 0.1 to 0.7. In particular, we study the various quantities like average and maximum density, collision rate, participant-spectator matter, anisotropic ratio, relative momentum as well as their mass asymmetry and mass dependence. We find sizeable effects of mass asymmetry on these quantities. Our results indicate that the mass dependence of various quantities increases slightly with increase in $eta$.
Using the quantum molecular dynamics model, we study the role of mass asymmetry of colliding nuclei on the fragmentation at the balance energy and on its mass dependence. The study is done by keeping the total mass of the system fixed as 40, 80, 160,
and 240 and by varying the mass asymmetry of the ($eta$ = $frac{A_{T}-A_{P}}{A_{T}+A_{P}}$; where $A_{T}$ and $A_{P}$ are the masses of the target and projectile, respectively) reaction from 0.1 to 0.7. Our results clearly indicate a sizeable effect of the mass asymmetry on the multiplicity of various fragments. The mass asymmetry dependence of various fragments is found to increase with increase in total system mass (except for heavy mass fragments). Similar to symmetric reactions, a power law system mass dependence of various fragment multiplicities is also found to exit for large asymmetries.
We study the role of impact parameter on the collective flow and its disappearance for different mass asymmetric reactions. The mass asymmetry is varied from 0 to 0.7 keeping the total mass of the system fixed. Our results clearly indicate a signific
ant role of impact parameter on the collective flow and its disappearance for the mass asymmetric reactions. The impact parameter dependence is also found to vary with mass asymmetry of the reaction.
We study the formation of fragments by extending the minimum spanning tree method (MST) for clusterization. In this extension, each fragment is subjected to a binding-energy check calculated using the modified Bethe-Weizsacker formula. Earlier, a con
stant binding-energy cut of 4 MeV/nucleon was imposed. Our results for 197Au +197 Au collisions are compared with ALADiN data and also with the calculations based on the simulated annealing technique. We shall show that the present modified version improves the agreement compared to the MST method.
We performed a systematic study of the formation of fragments with different mass ranges in 197Au+197Au collisions at incident energies between 20 - 1000 MeV/nucleon and at impact para- meter between ^b = 0-0.98. The aim of present study is to unders
tand the complex dependence of fragment production on incident energy and impact parameter. Our results clearly indicate that the QMD simulations of 197Au+197Au predict different behavior for different mass ranges than for IMFs with a change in incident energy and impact parameter. All charge yields can be parameterized by a power law and no signal of liquid-gas phase transition is seen as no unique dependence of tau on impact parameter is seen.
