Quenching of Single-Particle Strength in A=15 Nuclei

Area of Science:

• Nuclear Physics
• Nuclear Reactions
• Quantum Chemistry

Background:

• Understanding neutron addition to light nuclei like Carbon-14 (¹⁴C) and Nitrogen-14 (¹⁴N) is crucial for nuclear structure studies.
• Previous studies using different reaction mechanisms yielded varying insights into single-particle orbital occupancies.

Purpose of the Study:

• To precisely determine absolute cross sections for s- and d-wave neutron addition to ¹⁴C and ¹⁴N.
• To investigate the population of specific single-particle orbitals (1s₁/₂ and 0d₅/₂) in these nuclei.
• To compare findings with theoretical models and results from other reaction types.

Main Methods:

• Utilized the deuteron-proton (d,p) reaction at 10 MeV/u.
• Employed a simultaneous measurement technique to minimize systematic uncertainties.
• Analyzed the energy and angular distributions of the outgoing protons.

Main Results:

• Absolute cross sections for neutron addition to ¹⁴C and ¹⁴N were determined.
• The population of the 1s₁/₂ and 0d₅/₂ orbitals was found to be reduced by approximately 0.5-0.6 compared to theoretical predictions (independent single-particle and shell models).
• These results contrast significantly with data from intermediate-energy knockout reactions.

Conclusions:

• The study provides accurate cross-section data for neutron addition to ¹⁴C and ¹⁴N.
• Observed reduction in orbital populations suggests limitations in current single-particle models for these systems.
• The discrepancy with knockout reaction data highlights the importance of reaction mechanism dependence in nuclear structure investigations.