Speaker
Description
Introduction
The synthesis of neutron-rich heavy nuclei is essential for exploring study of islands of stability and understanding the astrophysical r-process. However, conventional fusion reactions have significant limitations in producing neutron-rich nuclei in the heavy and superheavy mass regions. In recent years, multinucleon transfer (MNT) reactions have therefore attracted considerable attention as a promising alternative method for producing such nuclei [1]. Nevertheless, the reaction mechanism of MNT processes remains poorly understood because of their complex dynamical nature. A quantitative understanding of the reaction dynamics is required to reliably predict the production cross sections and other physical properties of evaporation residues (ERs). In this study, we develop a dynamical model to describe MNT reaction processes and evaluate its validity through comparisons with experimental data. Our goal is to clarify the MNT reaction mechanism and establish a reliable framework for predicting the production of neutron-rich heavy and superheavy nuclei.
Method
In this study, we employ a Langevin-type dynamical model as a theoretical framework for describing MNT reactions. This model describes the time evolution of the nuclear shape, thereby enabling us to follow the reaction dynamics throughout the collision process. It also allows for direct comparisons between the calculated results and experimental data. The nuclear shape is represented using the two-center shell model [2,3], and the corresponding potential energy surface is calculated for each nuclear configuration. The reaction dynamics are then investigated by solving multidimensional Langevin equations to calculate the shape trajectories evolving on the potential energy surface [4].
Result & Discussion
Our model had previously treated only the mass-asymmetry. In the present study, we introduce the charge-asymmetry into the model and perform calculations of the MNT reaction for the 136Xe + 198Pt system[5]. Comparisons with experimental data demonstrate that the model can reproduce both the mass and charge distributions. In this presentation, in addition to comparing the calculated results with the experimental data, we discuss the effects of the nuclear orientation at contact and the friction acting during the contact stage.
References
[1] V. Zagrebaev, et al., Phys Rev C 73, (2006) 031602.
[2] J. Maruhn and W. Greiner, Z. Phys 251, (1972) 431.
[3] V. Zagrebaev and W. Greiner, J. Phys. G 34, (2007) 2265-2277.
[4] S. Amano, et al., Phys Rev C 109, (2024) 034603.
[5] V. V. Desai, et al., Eur, Phys. J A, (2020) 56:150.