Cause of systematic underestimation of charge-changing cross sections by Glauber-model calculations

Determine the physical origin of the normalization required to match Glauber-model (optical-limit approximations) calculations of charge-changing cross sections to measured values for stable nuclei at hundreds to thousands of MeV per nucleon, and quantify the contributions of candidate processes such as proton evaporation following neutron removal and proton–neutron exchange, including possible target-dependent effects between hydrogen and carbon.

Background

To deduce proton radii from charge-changing cross sections, the Glauber model is commonly used. However, calculated cross sections are systematically smaller than experimental values, and analyses often introduce an empirical normalization to match data for stable nuclei.

The authors note that the reason for this discrepancy is not yet understood. Proposed mechanisms include proton evaporation after neutron removal and a proton–neutron exchange process, with potential differences between hydrogen and carbon targets. Resolving this issue is important for reliable extraction of proton radii, especially for exotic nuclei.