In-medium Cross Section Impacts Cluster Spectra in Collisions at And, Study Shows

Understanding how nuclear matter behaves under extreme conditions, such as those created in heavy-ion collisions, remains a central challenge in nuclear physics. C. K. Tam, Z. Chaj\k, R. S. Wang, and colleagues investigate the crucial role of in-medium nucleon-nucleon interactions in shaping the outcomes of these collisions.

The team focuses on analysing the spectra of particles, including protons, neutrons, and other composite particles, produced in central collisions at specific energies, using a sophisticated transport model to simulate the collision dynamics. Their findings reveal a significant energy dependence in the reduction of nucleon-nucleon scattering cross-sections, demonstrating that the interactions between particles change considerably depending on the energy of the collision and offering new insights into the complex behaviour of nuclear matter under extreme conditions.

The team combines experimental data from projectile fragmentation with theoretical modelling to understand the parameters governing nuclear interactions. A key goal is to determine the symmetry energy, a crucial component of the equation of state that influences the stability of neutron-rich nuclei and the dynamics of core-collapse supernovae. Researchers analyse exotic nuclei formed in projectile fragmentation reactions, measuring their yields, energies, and isotopic compositions to reconstruct the properties of the nuclear system at various densities and temperatures. This experimental data is then compared with predictions from advanced theoretical models, such as density functional theory and molecular dynamics simulations, to refine our understanding of nuclear forces and the behaviour of matter under extreme conditions. Specific achievements include improved constraints on the density dependence of the symmetry energy, achieved through a combined analysis of experimental data and theoretical modelling, and the development of new methods for extracting information about the symmetry energy from the isotopic distributions of projectile fragments, enhancing the precision of existing measurements. Furthermore, the research provides insights into the role of nuclear clustering and many-body correlations in shaping the properties of exotic nuclei, contributing to a more complete picture of nuclear structure and dynamics.,.

Dense Nuclear Matter and Heavy-Ion Collisions Research focuses on understanding the behaviour of nuclear matter under extreme conditions created in heavy-ion collisions. Scientists analyse the spectra of particles, including protons, neutrons, and composite particles, produced in central collisions at specific energies, using sophisticated transport models to simulate the collision dynamics. Their findings reveal a significant energy dependence in the reduction of nucleon-nucleon scattering cross-sections, demonstrating that the interactions between particles change considerably depending on the energy of the collision and offering new insights into the complex behaviour of nuclear matter under extreme conditions.,.

Dense Matter Impacts Nucleon Interaction Spectra Scientists have achieved a detailed understanding of how nuclear forces change within extremely dense matter, using data from collisions of atomic nuclei. The research focuses on the behaviour of nucleons, protons and neutrons, and light composite particles like deuterons, tritons, and alpha particles, produced in collisions between calcium and nickel nuclei at incident energies of 56 and 140 MeV per nucleon. Experiments revealed the transverse momentum spectra of these particles emitted near mid-rapidity, providing insights into the in-medium nucleon-nucleon scattering cross-section.

The team employed the Antisymmetrized Molecular Dynamics model to simulate these nuclear collisions and compare the results with experimental data. Calculations demonstrate that the nucleon-nucleon scattering cross-section is significantly reduced when nucleons are packed closely together within the dense nuclear medium. Measurements confirm a stronger reduction in the cross-section at the lower incident energy of 56 MeV/nucleon compared to 140 MeV/nucleon, indicating a density-dependent effect on the nuclear interaction. Specifically, the research establishes that the in-medium effect is more pronounced at lower energies, suggesting a greater sensitivity to density changes under these conditions. These measurements are crucial for understanding the dynamics of the dense nuclear medium and the behaviour of nucleons within it, delivering a refined understanding of the in-medium nucleon-nucleon interaction, which is essential for modelling neutron stars and understanding the properties of dense matter in astrophysical environments.,.

Dense Matter Modifies Nuclear Particle Interactions This research presents a detailed analysis of nuclear collisions, specifically investigating how the density of nuclear matter affects the interactions between particles produced during these events. Scientists examined collisions involving calcium isotopes at varying energies, tracking the emitted particles to understand the in-medium nucleon-nucleon scattering cross-section.

The team successfully compared experimental data with predictions from the Antisymmetrized Molecular Dynamics model, allowing for a refined understanding of these interactions. The results demonstrate that the reduction in the nucleon-nucleon scattering cross-section is more pronounced at higher collision energies, providing valuable insight into the behaviour of nuclear matter under extreme conditions and contributing to a more accurate description of the forces governing interactions within atomic nuclei and during astrophysical events like neutron star mergers. The study acknowledges limitations related to the complexity of modelling nuclear collisions and the inherent uncertainties in determining the precise impact parameter of each event, suggesting future research directions include refining the theoretical models to better capture the nuances of these interactions and exploring a wider range of collision systems to further validate the findings. 👉 More information 🗞 Impact of the in-medium cross section on cluster spectra in collisions at and 🧠 ArXiv: https://arxiv.org/abs/2512.10193 Tags: