155 research outputs found
Elastic Scattering of He based on a Cluster Description
Elastic scattering observables (differential cross section and analyzing
power) are calculated for the reaction He(p,p)He at projectile energies
starting at 71 MeV/nucleon. The optical potential needed to describe the
reaction is derived describing He in terms of a He-core and two
neutrons. The Watson first order multiple scattering ansatz is extended to
accommodate the internal dynamics of a composite cluster model for the He
nucleus scattering from a nucleon projectile. The calculations are compared
with the recent experiments at the projectile energy of 71 MeV/nucleon. In
addition, differential cross sections and analyzing powers are calculated at
selected higher energies.Comment: To be published in Phy. Rev.
Ab initio Folding Potentials for Nucleon-Nucleus Scattering based on NCSM One-Body Densities
Calculating microscopic optical potentials for elastic nucleon-nucleus
scattering has already led to large body of work in the past. For folding
first-order calculations the nucleon-nucleon (NN) interaction and the one-body
density of the nucleus were taken as input to rigorous calculations in a
spectator expansion of the multiple scattering series.
Based on the Watson expansion of the multiple scattering series we employ a
nonlocal translationally invariant nuclear density derived from a chiral
next-to-next-to-leading order (NNLO) and the very same interaction for
consistent full-folding calculation of the effective (optical) potential for
nucleon-nucleus scattering for light nuclei.
We calculate scattering observables, such as total, reaction, and
differential cross sections as well as the analyzing power and the
spin-rotation parameter, for elastic scattering of protons and neutrons from
He, He, C, and O, in the energy regime between 100 and
200~MeV projectile kinetic energy, and compare to available data.
Our calculations show that the effective nucleon-nucleus potential obtained
from the first-order term in the spectator expansion of the multiple scattering
expansion describes experiments very well to about 60 degrees in the
center-of-mass frame, which coincides roughly with the validity of the NNLO
chiral interaction used to calculate both the NN amplitudes and the one-body
nuclear density.Comment: 10 pages, 14 figures, 1 tabl
Adding Corrections to Global Spherical Potentials for Use in a Coupled-Channel Formulation
The coupled-channel technique augments a non-relativistic distorted wave born
approximation scattering calculation to include a coupling to virtual states
from the negative energy region. It has been found to be important in low
energy nucleon-nucleus scattering. We modify the nucleon-nucleus standard
optical potentials, not designed for a coupled-channel space, so they can be
used in that setting. The changes are small and systematic. We use a standard
scattering code to adjust a variety of optical potentials and targets such that
the original fit to scattering observables are maintained as we incorporate the
coupled-channel environment. Overall over forty target nuclei were tested from
to and nucleon projectile energies from 1 MeV to 200 MeV. There
is excellent improvement in fitting the scattering observables, especially for
low energy neutron scattering.The corrections were found to be unimportant for
projectile energies greater than 200 MeV. The largest changes are to the
surface amplitudes while the real radii and the real central amplitude are
modified by only a few percent, every other parameter is unchanged. This
technique is general enough to be applied to a variety of inelastic theoretical
calculations.Comment: Second draft, not yet submitted to a journal in this for
Nuclear structure and elastic scattering observables obtained consistently with different NN interactions
Nucleon-nucleon () interactions based on chiral effective theories are
commonly used in ab initio calculations of light nuclei. Here we present a
study based on three different NN interactions (up to next-to-next-to-leading
order) for which structure and elastic proton scattering observables are
consistently calculated for He, C, and O. The interactions
are compared at the two-body level in terms of Wolfenstein amplitudes, and
their predictions for ground state energies, point-proton radii, and charge
form factors, as well as proton elastic scattering observables in the
leading-order spectator expansion in the energy range between 65 and 160 MeV
projectile energy are presented. To gain further insight into differences
visible in elastic scattering observables, we investigate the behavior of the
calculated effective nucleon-nucleus interactions for the C nucleus
based on the different interactions.Comment: 17 pages, 17 figure
Ab initio Folding Potentials for Proton-Nucleus Scattering with NCSM Nonlocal One-Body Densities
Based on the spectator expansion of the multiple scattering series we employ a nonlocal translationally invariant nuclear density derived from a chiral next-to-next-to-leading order (NNLO) and the very same interaction for consistent full-folding calculations of the effective (optical) potential for nucleon-nucleus scattering for light nuclei
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