Speaker
Description
Intermediate-energy heavy-ion reactions provide essential tools for studying nuclear sizes, fragmentation mechanisms, single-particle strength, and isospin dynamics in stable and exotic nuclei. Traditionally, many inclusive reaction cross sections have been interpreted as rather direct probes of nuclear structure, such as proton radii from charge-changing cross sections, spectroscopic strength from nucleon-removal reactions, and isospin response from charge-pickup reactions. However, recent systematic studies show that the measured final residues are often strongly reshaped by the de-excitation of excited prefragments produced in the fast collision stage.
In this talk, I will discuss recent progress in understanding such reaction observables through the concept of an evaporation filter. Using charge-changing cross sections, elemental fragmentation cross sections, single-nucleon removal, and charge-pickup reactions as representative examples, I will show how charged-particle evaporation, neutron/proton evaporation competition, excitation-energy distributions, and survival probabilities modify the observed cross sections. The transport-plus-de-excitation framework, especially IQMD combined with GEMINI, provides event-history information that helps separate primary production, evaporation feeding, and evaporation loss.
These studies indicate that inclusive cross sections are not always direct structure observables. Instead, they are filtered by reaction mechanisms after the fast collision. Understanding this evaporation filter is therefore essential for extracting reliable nuclear radii, single-particle strength, and neutron-rich surface information from intermediate-energy reaction data.