Isospin migration within fast-rotating heavy ion collision system

Exploring the Isospin Dynamics Within Fast-rotating Heavy Ion Collision System
Led by physicist Zhigang Xiao and Yijie Wang, the research team has documented that fast-rotating Fermi energy heavy ion collision system undergoes a unique isospin migration mechanism, where more neutron-rich particles are emitted from out-of-fission-plane. This process refined the isospin dynamics transport properties of the rapidly rotating heavy ion collision system, providing a new opportunity for the study of the symmetry energy properties of the equation of state of nuclear matter.

Probing the Ultra-fast Subatomic Process Using Advanced Detection System
Aiming at the equation of state of nuclear matter and isospin dynamical transport properties, which are the common frontier topics of nuclear physics and astrophysics. After ten years' efforts, the research group has built a Compact Spectrometer for Heavy IoN Experiment (CSHINE), an advanced detection system. Currently, CSHINE is composed of silicon strip telescope, parallel plate avalanche chamber, high-energy gamma array and neutron array, which can realize the measurement of charged particles, fission fragments, photons and neutrons. Significantly, this research work benefits from the good coincidence measurement ability of charged particles and fission fragments of CSHINE, and the advanced detection system is the key to carry out this novel observation.

Imaging the Isospin Migration within Fast-rotating Heavy Ion Collision
Measuring the three-body coincidence event of one light charged particle and two fission fragments, researchers have reconstructed the fission plane and analyzed isospin space distribution in the fast-rotating heavy ion collision system. This approach provides a vivid view of the isospin migration dynamics, allowing for a more accurate understanding of isospin transport properties in heavy ion collision process. The novel observation of the enhancement of neutron-rich particle emission from out-of-fission-plane gives us the new opportunity to deeply understanding the nuclear matter in extreme conditions.

Implications for Science and Technology
This study enriches academic knowledge and has practical applications. Understanding isospin migration in fast-rotating heavy ion collisions can drive progress in nuclear astrophysics, helping us better grasp what happens in neutron stars and supernovae, where extreme densities and isospin effects are common. In nuclear energy, it can support the development of more efficient and safer reactors by clarifying nuclear reactions and how nuclear matter behaves under high-energy, high-angular-momentum states.

Advancing Nuclear Physics Research
The team is now set to explore further how the initial properties of heavy ion influences the isospin transport processes in heavy ion collisions. Future research aims to delve into the relationships between novel observations and the fundamental properties of nuclear matter, with the potential to advance the experiment studies in nuclear physics extensively.

The complete study is accessible via DOI: 10.1007/s41365-025-01742-z.

Nuclear Science and Techniques (NST) is a peer-reviewed international journal sponsored by the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. The journal publishes high-quality research across a broad range of nuclear science disciplines, including nuclear physics, nuclear energy, accelerator physics, and nuclear electronics. Its Editor-in-Chief is the renowned physicist, Professor Yu-Gang Ma.