Nuclear Dynamics at the Balance Energy

We study the mass dependence of various quantities (like the average and maximum density, collision rate, participant-spectator matter, temperature as well as time zones for higher density) by simulating the reactions at the energy of vanishing flow. This study is carried out within the framework of Quantum Molecular Dynamics model. Our findings clearly indicate an existence of a power law in all the above quantities calculated at the balance energy. The only significant mass dependence was obtained for the temperature reached in the central sphere. All other quantities are rather either insensitive or depend weakly on the system size at balance energy. The time zone for higher density as well as the time of maximal density and collision rate follow a power law inverse to the energy of vanishing flow.Comment: 9 figures, Submitted to Phys. Rev.

Systematic study of the energy of vanishing flow: Role of equations of state and cross sections

We present a systematic study of the energy of vanishing flow by considering symmetric colliding nuclei (between $^{12}$C and $^{238}$U) at normalized impact parameters using variety of equations of state (with and without momentum dependent interactions) as well as different nucleon-nucleon cross sections. A perfect power law mass dependence is obtained in all the cases which passes through calculated points nicely. Further, the choice of impact parameter affects the energy of vanishing flow drastically, demanding a very accurate measurement of the impact parameter. However, the energy of vanishing flow is less sensitive towards the equation of state as well as its momentum dependence.Comment: 9 pages, 2 figure

The study of participant-spectator matter and collision dynamics in heavy-ion collisions

We present the simulations of heavy-ion collisions in terms of participant-spectator matter. We find that this matter depends crucially on the collision dynamics and history of the nucleons. The important changes in the momentum space are due to the binary nucleon-nucleon collisions experienced during the high dense phase. This was otherwise not possible with mean field alone. The collisions push the colliding nucleons into midrapidity region responsible for the formation of participant matter. This ultimately leads to thermalization in heavy-ion collisions.Comment: 15 pages, 8 figure

Participant-spectator matter at the energy of vanishing flow

We aim to study the participant-spectator matter over a wide range of energies of vanish- ing flow and masses. For this, we have employed different model parameters at central and semi-central colliding geometries. A nearly mass independent nature of the participant matter has been obtained at the energy of vanishing flow. Further, participant matter can also act as an indicator to study the degree of thermalization.Comment: Proceedings of the International Symposium on Nuclear Physics, Mumbai (INDIA), Vol. 54 pg. 452 (2009

On the balance energy and nuclear dynamics in peripheral heavy-ion collisions

We present here the system size dependence of balance energy for semi-central and peripheral collisions using quantum molecular dynamics model. For this study, the reactions of $Ne^{20}+Ne^{20}$, $Ca^{40}+Ca^{40}$, $Ni^{58}+Ni^{58}$, $Nb^{93}+Nb^{93}$, $Xe^{131}+Xe^{131}$ and $Au^{197}+Au^{197}$ are simulated at different incident energies and impact parameters. A hard equation of state along with nucleon-nucleon cross-sections between 40 - 55 mb explains the data nicely. Interestingly, balance energy follows a power law $\propto{A^{\tau}}$ for the mass dependence at all colliding geometries. The power factor $\tau$ is close to -1/3 in central collisions whereas it is -2/3 for peripheral collisions suggesting stronger system size dependence at peripheral geometries. This also suggests that in the absence of momentum dependent interactions, Coulomb's interaction plays an exceedingly significant role. These results are further analyzed for nuclear dynamics at the balance point.Comment: 13 pages, 9 figures Accepted in IJMPE (in press