We present our current studies and our future plans on microscopic potential based on effective nucleon-nucleon interaction and many-body theory. This framework treats in an unified way nuclear structure and reaction. It offers the opportunity to lin
k the underlying effective interaction to nucleon scattering observables. The more consistently connected to a variety of reaction and structure experimental data the framework will be, the more constrained effective interaction will be. As a proof of concept, we present some recent results for both neutron and proton scattered from spherical target nucleus, namely 40 Ca, using the Gogny D1S interaction. Possible fruitful crosstalks between microscopic potential, phenomenological potential and effective interaction are exposed. We then draw some prospective plans for the forthcoming years including scattering from spherical nuclei experiencing pairing correlations, scattering from axially deformed nuclei, and new effective interaction with reaction constraints.
The effect of in-medium dinucleon bound states on self-consistent single-particle fields in Brueckner, Bethe and Goldstone theory is investigated in symmetric nuclear matter at zero temperature. To this end, dinucleon bound state occurences in the $^
1S_0$ and ${}^3SD_1$ channels are explicitly accounted for -within the continuous choice for the auxiliary fields- while imposing self-consistency in Brueckner-Hartree-Fock approximation calculations. Searches are carried out at Fermi momenta in the range $0<k_Fleq1.75$~fm$^{-1}$, using the Argonne $v_{18}$ bare nucleon-nucleon potential without resorting to the effective mass approximation. As a result, two distinct solutions meeting the self-consistency requirement are found with overlapping domains in the interval $0.130;textrm{fm}^{-1} leq k_F leq 0.285;textrm{fm}^{-1}$, corresponding to mass densities between $10^{11.4}$ and $10^{12.4}$ g cm$^{-3}$. Effective masses as high as three times the nucleon mass are found in the coexistence domain. The emergence of superfluidity in relationship with BCS pairing gap solutions is discussed.
We present nucleon elastic scattering calculation based on Greens function formalism in the Random-Phase Approximation. For the first time, the Gogny effective interaction is used consistently throughout the whole calculation to account for the compl
ex, non-local and energy-dependent optical potential. Effects of intermediate single-particle resonances are included and found to play a crucial role in the account for measured reaction cross section. Double counting of the particle-hole second-order contribution is carefully addressed. The resulting integro-differential Schrodinger equation for the scattering process is solved without localization procedures. The method is applied to neutron and proton elastic scattering from $^{40}$Ca. A successful account for differential and integral cross sections, including analyzing powers, is obtained for incident energies up to 30 MeV. Discrepancies at higher energies are related to much too high volume integral of the real potential for large partial waves. Moreover, this works opens the way for future effective interactions suitable simultaneously for both nuclear structure and reaction.
Angular correlations arising from particle-particle (pp) propagation in nuclear matter are investigated. Their account follows an exact treatment of the Pauli exclusion principle on intermediate states in the Bruekner-Bethe-Goldstone (BBG) equation.
As a result, a correlation form factor emerges from the Cauchy principal-value of the pp propagator, while the imaginary part becomes structurally different from those in Lippmann-Schwinger-type equations. These novel features modify drastically the behaviour of the mass operator near the Fermi surface, reshaping the phase-space where its imaginary part vanishes and sliding down the saturation point of symmetric nuclear matter along the Coester band. The correlation structures found here --which go beyond angle-averaged (or effective-mass type) energy denominators-- may impact present day model predictions for neutron stars based on the BBG equation, and for scattering and reaction observables in full folding optical model calculations
