Transition properties of low-lying states in $^{28}$Si probed via inelastic proton and alpha scattering

Abstract

+ , 1 − , 2 + , and 3 − excitations of 28 Si are investigated via proton and α inelastic scattering off 28 Si. The structure calculation of 28 Si is performed with the energy variation after total angular momentum and parity projections in the framework of antisymmetrized molecular dynamics (AMD). As a result of the AMD calculation, the oblate ground and prolate bands, 0 + and 3 − excitations, and the 1 − and 3 − states of the K π = 0 − band are obtained. Using the matter and transition densities of 28 Si obtained by AMD, microscopic coupled-channel calculations of proton and α scattering off 28 Si are performed. The proton-28 Si potentials in the reaction calculation are microscopically derived by folding the Melbourne g-matrix N N interaction with the AMD densities of 28 Si. The α-28 Si potentials are obtained by folding the nucleon-28 Si potentials with an α density. The calculation reasonably reproduces the observed elastic and inelastic cross sections of proton and α scattering. Transition properties are discussed by combining the reaction analysis of proton and α scattering and structure features such as transition strengths and form factors. The isoscalar monopole and dipole transitions are focused.

Properties of $K^π=0^+_1$, $K^π=2^-$, and $K^π=0^-_1$ bands of $^{20}$Ne probed via proton and alpha inelastic scattering

“…Elastic and inelastic cross sections of proton and α scattering off 20 Ne are calculated with the MCC approach as done in our previous studies of Refs. [32][33][34][35]. For the details of the reaction calculations, the reader is referred to those references.…”

“…The Melbourne g matrix is an effective N N interaction derived with a bare N N interaction of the Bonn B potential [37]. It contains energy and density dependences with no adjustable parameter, and works well in application for systematic description of proton elastic and inelastic scattering off various nuclei at energies E p =40-300 MeV [34][35][36][51][52][53] and also α elastic and inelastic scattering at energies E α =100-400 MeV [32,33,35,50,54]. In the present calculation of the proton-nucleus potentials, the spin-orbit term of the potential is not taken into account to avoid complexity as in Refs.…”

“…In the present calculation of the proton-nucleus potentials, the spin-orbit term of the potential is not taken into account to avoid complexity as in Refs. [34,35].…”

“…In the MCC calculations, matter and transition densities of target nuclei obtained with microscopic structure models are utilized as inputs of coupled-channel reaction calculations in microscopic folding models (MFMs), in which nucleon-nucleus and α-nucleus potentials are constructed by folding effective N N interactions. In our previous studies [32][33][34][35], we have applied the MCC calculations to proton and α scattering off various target nuclei in the p-and sd-shell regions with structure model calculation of AMD. Using the Melbourne g-matrix N N interaction [36], we have succeeded in reproducing (p, p ) and (α, α ) cross sections of various excited states such as cluster and vibration excitations.…”