Hybrid model for studying nuclear multifragmentation around the Fermi energy domain: The case of central collisions of Xe on Sn

Experimental data for central collisions of ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ at beam energies of (a) 32, (b) 39, (c) 45, and (d) 50 MeV/nucleon are compared with results calculated using a hybrid model. We use a transport model (BUU) to obtain the excitation energy per nucleon in the center of mass of the multifragmenting system. The canonical thermodynamic model is then used to determine the temperature which would lead to this excitation energy. With this temperature we use the canonical thermodynamic model to calculate various experimental data such as multiplicities of different composites, probability distribution of the largest cluster, etc. Agreement with data establishes the validity of the model.

Figure 1

Evolution of test particles at (a) 0, (b) 75, and (c) 200 fm/c in the center-of-mass frame for 45 MeV/nucleon ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ reaction.

Figure 2

Variation of energy of the central dense region (containing $80\%$ of total test particles) with time obtained from dynamical BUU calculation for ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ reaction at 45 MeV/nucleon.

Figure 3

Left panel indicates the variation of excitation energy per nucleon with projectile beam energy per nucleon obtained from dynamical BUU model. The canonical thermodynamical model (CTM) can calculate average excitation energy per nucleon for a given freeze-out temperature, mass number, and charge. Therefore to know the required freeze-out temperature corresponding to each excitation (obtained from BUU calculation), CTM is used. The variation of freeze-out temperature with projectile beam energy is shown in the right panel.

Figure 4

Theoretical charge distribution (red [gray] dotted lines) for ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ reaction at (a) 32, (b) 39, (c) 45, and (d) 50 MeV/nucleon. The experimental data are shown by black squares.

Figure 5

Theoretical largest cluster probability distribution (red [gray] dotted lines) for ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ reaction at (a) 32, (b) 39, (c) 45, and (d) 50 MeV/nucleon. The experimental data are shown by black squares.

Figure 6

Variation of average size of largest cluster with projectile beam energy obtained from hybrid model calculation (red [gray] dotted lines) for ${}^{129}\mathrm{Xe}$ on ${}^{119}\mathrm{Sn}$ reaction. The experimental data are shown by black squares.