Microscopic Optical Potential from
Chiral Effective Field Theory
T. R. Whitehead, Y. Lim, and J. W. Holt
1 Chiral Nuclear Optical Model Potentials
Optical model potentials are widely used to predict nucleon–nucleus scattering
cross sections and reaction observables by replacing the complicated many-body
system of nucleons interacting through two- and three-body forces with an average
complex and energy-dependent single-particle potential. Phenomenological models
[1] fitted to experimental data are very successful at describing scattering processes
for nuclei near stability, but high-quality microscopic optical potentials may be
more reliable for reactions involving exotic isotopes for which experimental data
are scarce. Recently, microscopic optical potentials in homogeneous nuclear matter
have been constructed [2, 3] based on realistic chiral two- and three-body forces.
The aim of the present work is to extend this description to the case of finite nuclei,
with a special focus on proton elastic scattering off calcium isotopes.
In quantum many-body theory, the nuclear optical potential is identified with
the nucleon self-energy. We begin by computing the nucleon self-energy in infinite
homogeneous nuclear matter at a given density and isospin asymmetry starting from
a realistic chiral nuclear interaction [4] with momentum-space cutoff = 450 MeV.
The real and imaginary central terms of the optical potential arise naturally when
the nucleon self-energy is computed to second order in many-body perturbation
theory. The real spin–orbit term cannot be extracted from nuclear matter calculations
and in the present work is instead calculated from the Negele–Vautherin density
matrix expansion [5] using the same chiral potential. The density-dependent optical
T. R. Whitehead () · Y. Lim · J. W. Holt
Cyclotron Institute, Texas A&M University, College Station, TX, USA
Department of Physics and Astronomy, Texas A&M University, College Station, TX, USA
e-mail: twhitehead@tamu.edu
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_11
91
Chiral Effective Field Theory
T. R. Whitehead, Y. Lim, and J. W. Holt
1 Chiral Nuclear Optical Model Potentials
Optical model potentials are widely used to predict nucleon–nucleus scattering
cross sections and reaction observables by replacing the complicated many-body
system of nucleons interacting through two- and three-body forces with an average
complex and energy-dependent single-particle potential. Phenomenological models
[1] fitted to experimental data are very successful at describing scattering processes
for nuclei near stability, but high-quality microscopic optical potentials may be
more reliable for reactions involving exotic isotopes for which experimental data
are scarce. Recently, microscopic optical potentials in homogeneous nuclear matter
have been constructed [2, 3] based on realistic chiral two- and three-body forces.
The aim of the present work is to extend this description to the case of finite nuclei,
with a special focus on proton elastic scattering off calcium isotopes.
In quantum many-body theory, the nuclear optical potential is identified with
the nucleon self-energy. We begin by computing the nucleon self-energy in infinite
homogeneous nuclear matter at a given density and isospin asymmetry starting from
a realistic chiral nuclear interaction [4] with momentum-space cutoff = 450 MeV.
The real and imaginary central terms of the optical potential arise naturally when
the nucleon self-energy is computed to second order in many-body perturbation
theory. The real spin–orbit term cannot be extracted from nuclear matter calculations
and in the present work is instead calculated from the Negele–Vautherin density
matrix expansion [5] using the same chiral potential. The density-dependent optical
T. R. Whitehead () · Y. Lim · J. W. Holt
Cyclotron Institute, Texas A&M University, College Station, TX, USA
Department of Physics and Astronomy, Texas A&M University, College Station, TX, USA
e-mail: twhitehead@tamu.edu
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_11
91