Nuclear dynamics at the balance energy

Abstract

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.

Participant-spectator matter at the energy of vanishing flow

“…However, at semiperipheral geometries (b/b max = 0.6), all three participant matters (i.e., PM-R1, PM-R2, and PM-R3) decrease with increase in the incident energy which may be due to the fact that the dominance of mean field at low incident energies and higher impact parameter causes the thermalization in a reaction. It has been reported in Ref [29]. that the nature of participant-spectator matter is not altered by the mass of the colliding nuclei.…”

“…It was argued that due to small number of nucleon-nucleon collisions in lighter colliding nuclei, one needs higher incident energies to reach the balance point. In our earlier report, [29] participant-spectator matter has been reported to be almost constant at EVF for entire periodic table in central collisions. This happens because of the fact that at the balance energy, the attractive and repulsive forces counterbalance each other.…”

“…The extraction and discussion has been reported elsewhere [28]. Once the energy of vanishing flow is known, the participant-spectator matter is extracted with two different procedures as explained in Ref [29]. (a) All nucleons having experienced at least one collision are counted as participant matter (labeled as PM-C).…”

“…For the first time, we reported that the participant-spectator matter at EVF is quite insensitive to the mass of the colliding system. It, therefore, can act as a barometer for the study of the energy of vanishing flow [29]. Here, we plan to extend the study of vanishing flow for other equations of state as well as for the momentum dependent interactions.…”

Neutron to proton ratio dependence of energy of vanishing flow: role of system size and collision geometry

“…System size dependencies have been reported for various phenomena like fusionfission, particle production, multifragmentation, collective flow (of nucleons/fragments) as well as its disappearance, for density and temperature and so on [1][2][3][4][5][6]. Low energy fusion processes deserve a special mention, where the mass dependence was analysed using hundred of reactions.…”