Multiple Mechanisms in Proton-Induced Nucleon Removal at ∼100  MeV/Nucleon

Area of Science:

• Nuclear Physics
• Rare Isotope Physics
• Nuclear Reactions

Background:

• Investigating neutron-deficient nuclei like oxygen-14 is vital for understanding nuclear structure.
• Proton-induced one-nucleon removal reactions are a key tool in rare-isotope studies at intermediate energies.
• Accurate interpretation requires understanding all contributing reaction mechanisms.

Purpose of the Study:

• To experimentally determine proton- and neutron-removal reaction mechanisms from oxygen-14.
• To quantify the contributions of quasifree knockout, inelastic scattering, and nucleon transfer.
• To compare experimental data with advanced reaction models and nuclear structure calculations.

Main Methods:

• Proton-induced single proton- and neutron-removal reactions were performed on oxygen-14 at approximately 100 MeV/nucleon.
• Inclusive cross sections and parallel momentum distributions of the resulting nitrogen-13 and oxygen-13 residues were measured.
• Data were analyzed using state-of-the-art reaction models incorporating many-body shell-model nuclear structure inputs.

Main Results:

• The first quantitative contributions of multiple reaction mechanisms (quasifree knockout, inelastic scattering, nucleon transfer) were identified.
• Inelastic scattering accounted for approximately 50% of proton removal.
• Nucleon transfer contributed about 30% to neutron removal, highlighting their significance.

Conclusions:

• Inelastic scattering and nucleon transfer are significant, often neglected, contributors to one-nucleon removal at intermediate energies.
• These mechanisms must be included in analyses of inclusive one-nucleon removal cross sections.
• Accurate consideration of multiple reaction channels is essential for quantitative studies of single-particle strengths and nuclear correlations.