Single-proton removal reaction in the IQMD+GEMINI model benchmarked by elemental fragmentation cross sections of $^{29-33}\mathrm{Si}$ on carbon at $\sim$230~MeV/nucleon

TL;DR

This study measures and models the elemental fragmentation cross sections of silicon isotopes on carbon at high energy, revealing the roles of proton and neutron evaporation in the reaction mechanisms.

Contribution

It provides the first experimental EFCS data for $^{29-33}$Si at ~230 MeV/nucleon and benchmarks the IQMD+GEMINI model against these measurements.

Findings

Direct proton knockout cross sections are weakly dependent on Si isotope mass.

Proton evaporation affects neutron-deficient Si isotopes significantly.

Neutron evaporation is crucial for neutron-rich Si isotopes.

Abstract

We report on the first measurement of the elemental fragmentation cross sections (EFCSs) of $^{29-33}\mathrm{Si}$ on a carbon target at $\sim$230~MeV/nucleon. The experimental data covering charge changes of $\Delta Z$ = 1-4 are reproduced well by the isospin-dependent quantum molecular dynamics (IQMD) coupled with the evaporation GEMINI (IQMD+GEMINI) model. We further explore the mechanisms underlying the single-proton removal reaction in this model framework. We conclude that the cross sections from direct proton knockout exhibit a overall weak dependence on the mass number of $\mathrm{Si}$ projectiles. The proton evaporation induced after the projectile excitation significantly affects the cross sections for neutron-deficient $\mathrm{Si}$ isotopes, while neutron evaporation plays a crucial role in the reactions of neutron-rich $\mathrm{Si}$ isotopes. It is presented that the relative magnitude of one-proton and one-neutron separation energies is an essential factor that influences evaporation processes.