# Entrance Channel Effects on the Quasifission Reaction Channel in Cr + W Systems

## TL;DR

This study investigates how entrance channel effects, especially deformation and neutron-richness, influence quasifission in Cr + W heavy-ion reactions near the interaction barrier, revealing deformation effects dominate over neutron-richness at low energies.

## Contribution

It provides new insights into the dominance of deformation effects over neutron-richness in quasifission at energies near the interaction barrier in Cr + W systems.

## Key findings

- Deformation effects dominate over neutron-richness in quasifission.
- Curvature parameter analysis correlates with reaction parameters.
- Neutron-richness effects are less significant at near-barrier energies.

## Abstract

Background: Formation of a fully equilibrated compound nucleus is a critical step in the heavy-ion fusion reaction mechanism but can be hindered by orders of magnitude by quasifission, a process in which the dinuclear system breaks apart prior to full equilibration. To provide a complete description of heavy-ion fusion it is important to characterize the quasifission process. In particular, the impact of changing the neutron-richness of the quasifission process is not well known. A previous study of Cr + W reactions at a constant 13 % above the Coulomb barrier concluded that an increase in neutron-richness leads to a decrease in the prominence of the quasifission reaction channel. Purpose: The interplay between the fusion-fission and quasifission reaction channels, with varying neutron-richness, was explored at a constant excitation energy, closer to the interaction barrier than the previous work, to see if the correlation between neutron-richness and quasifission is valid at lower energies. Methods: Mass distributions were determined for eight different combinations of Cr + W reactions at the Australian National University at 52.0 MeV of excitation energy in the compound nucleus. Results: A curvature parameter was determined for the fission-like fragment mass distributions and compared to various reaction parameters known to influence quasifission. Conclusions: The present work demonstrates that at energies near the interaction barrier the deformation effects dominate over the neutron-richness effects in the competition between quasifission and compound nucleus formation in these Cr + W systems and is an important consideration for future with heavy and superheavy element production reactions.