Nucleon- α scattering and resonances in He5 and Li5 with JISP16 and Daejeon16

Abstract

The SS-HORSE approach to analysis of resonant states is generalized to the case of charged particle scattering utilizing analytical properties of partial scattering amplitudes and applied to the study of resonant states in the 5 Li nucleus and non-resonant s-wave proton-α scattering within the no-core shell model using the JISP16 and Daejeon16 N N interactions. We present also the results of calculations of neutron-α scattering and resonances in the 5 He nucleus with Daejeon16 and compare with results published previously using JISP16.

A Guided Tour of ab initio Nuclear Many-Body Theory

“…Equation 38), andh andn encode the coupling between the sectors of the basis. Alternative approaches to the description of continuum effects in the NCSM are the Single-State HORSE (Harmonic Oscillator Representation of Scattering Equations) method [148][149][150], for which the nomen is omen, as well as the No-Core Gamow Shell Model (GSM), a no-core CI approach that constructs Slater determinants from a single-particle Berggren basis [151] consisting of bound, resonant and scattering states [152][153][154][155].…”

Resonances in Exotic $^7$He Nucleus within the No-Core Shell Model

“…Recently we proposed the SS-HORSE method [12][13][14][15][16][17], which generalizes the NCSM to the continuum states. The SS-HORSE allows one to calculate the single-channel S-matrix and resonances by a simple analysis of NCSM eigenenergy behavior as a function of parameters of the many-body oscillator basis.…”

“…The SS-HORSE extension of the NCSM was successfully applied to the calculation of the neutron-α and proton-α scattering and resonant states in the 5 He and 5 Li nuclei in Refs. [12,16]; a generalization of this approach to the case of the democratic decay provided a description of a resonance in the system of four neutrons (tetraneutron) [18]. The unbound 7 He nucleus presents a new challenge for ab initio theory but is especially interesting since its experimental information is fragmentary and conflicting.…”

“…Some tricks useful to design a stable and fast numerical algorithm for the pole searches at complex energies, are described in Ref. [16]. By locating the S-matrix poles, we obtain energies E r and widths Γ of resonances in the many-body nuclear system.…”

“…As stated in Refs. [12][13][14][15][16][17][18], we cannot use all relative motion energies E i = E 7…”