Description of the multinucleon transfer mechanism for ⁴⁸Ca+²⁴⁴Pu and ⁸⁶Kr+¹⁹⁸Pt reactions in a quantal transport approach

Background: Multinucleon transfer (MNT) reactions involving heavy projectile and target combinations stand as a promising method for synthesizing new neutron -rich exotic nuclei, which may not be possible using hot or cold fusion reactions or fragmentation. Exploring the mechanisms behind MNT reactions is essential and it requires a comprehensive theoretical framework that can explain the physical observables in these reactions. Purpose: This work aims to show that the quantal diffusion approach based on the stochastic mean -field (SMF) theory is capable of explaining the reaction dynamics observed in MNT reactions. Primary product mass distributions in 48Ca + 244Pu reaction at Ec.m. = 203.2 MeV and 86Kr + 198Pt reaction at Ec.m. = 324.2 MeV are calculated and compared with the available experimental data. Methods: In this work, we utilize the time -dependent Hartree-Fock (TDHF) calculations to analyze the meanfield reaction dynamics computationally in the reactions 48Ca+244Pu and 86Kr +198Pt for a broad range of initial angular momenta. Quantal transport description based on the SMF approach is used to calculate quantal diffusion coefficients and mass variances in 48Ca + 244Pu and 86Kr + 198Pt systems. The primary products arising from quasifission reactions are described by joint probability distribution in the SMF approach and those arising from fusion -fission are estimated by using the statistical deexcitation code GEMINI++. Results: Mean values of charge and mass numbers, scattering angles of the primary reaction products, and the total kinetic energies after the collision are calculated within the TDHF framework for a broad range of initial angular momenta. Throughout all the collisions, drift toward the mass symmetry and large mass dispersion associated with this drift are observed. The calculated primary fragment and mass distributions using the SMF approach successfully explain experimental observations for the 48Ca + 244Pu and 86Kr + 198Pt systems. Conclusions: The primary mass distributions, mean values of binary products, and mass dispersions are determined and results are compared with the available experimental data. The observed agreement between the experimental data and SMF results highlights the effectiveness of the quantal diffusion mechanism based on the SMF approach, which does not include any adjustable parameters other than standard parameters of Skyrme energy density functional.