Nonlocal interactions in the $(d,p)$ surrogate method for $(n,\gamma )$ reactions

Journal Article · 24 October 2018 · Physical Review C

DOI: https://doi.org/10.1103/PhysRevC.98.044621 · OSTI ID:1525886

Li, Weichuan ^[1]; Potel, Gregory ^[2]; Nunes, Filomena ^[3]

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1. Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Rutgers Univ., New Brunswick, NJ (United States). Dept. of Physics and Astronomy; MSU
2. Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.
3. Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab. Dept. of Physics and Astronomy

Single-neutron transfer reactions populating states in the continuum are interesting both for structure and astrophysics. In their description often global optical potentials are used for the nucleon-target interactions, and these interactions are typically local. In our work, we study the effects of nonlocality in $(d,p)$ reactions populating continuum states. This work is similar to that of Titus and Nunes [Phys. Rev. C 89, 034609 (2014)] but now for transfer to the continuum. A theory for computing cross sections for inclusive processes $A(d,p)X$ was explored in Potel et al. Therein, local optical potentials were used to describe the nucleon-target effective interaction. The goal of the present work is to extend the theory developed in Potel et al. (2015) to investigate the effects of including nonlocality in the effective interaction on the relevant reaction observables. We implement the $R$-matrix method to solve the nonlocal equations both for the nucleon wave functions and the propagator. We then apply the method to systematically study the inclusive process of $(d,p)$ on ${}_{16}\mathrm{O},{}_{40}\mathrm{Ca},{}_{48}\mathrm{Ca}$, and ${}_{208}\mathrm{Pb}$ at 10, 20, and 50 MeV. We compare the results obtained when nonlocal interactions are used with those obtained when local equivalent interactions are included. We find that nonlocality affects different pieces of the model in complex ways. The competition between the reduction of the propagator and the neutron wave function in the region of interest and the increase of the magnitude of the interaction produces varying effects on the cross section. Depending on the beam energy and the target, the nonelastic breakup can either increase or decrease. Effects on the heavier targets can be as large as $85\%$. While the nonelastic transfer cross section for each final spin state can change considerably, the main prediction of the model [Potel et al. (2015)], namely the shape of the spin distributions, remains largely unaltered by nonlocality.

• Research Organization: Michigan State Univ., East Lansing, MI (United States); Rutgers Univ., New Brunswick, NJ (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
• Grant/Contract Number: FG52-08NA28552; NA0000979; SC0013617
• OSTI ID: 1525886
• Journal Information: Physical Review C, Journal Name: Physical Review C Journal Issue: 4 Vol. 98; ISSN 2469-9985
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English