141 research outputs found
Ab-initio calculations of four-nucleon elastic scattering
We present microscopic calculations of low energy scattering observables in
all possible four nucleon systems : n-3H, p-3He and p-3H. Results were obtained
by solving Faddeev-Yakubovski equations in configuration space, appropriately
modified to include Coulomb and three-nucleon forces
Four nucleon systems : a zoom to the open problems in nuclear interaction
Faddeev-Yakubovski equations in configuration space are used to solve four
nucleon problem for bound and scattering states. Different realistic
interaction models are tested, elucidating open problems in nuclear interaction
description. On one hand, by example of nonlocal Doleschall potential, we
reveal possibility of reducing three-nucleon force. On the other hand we
disclose discrepancies in describing n+H resonance, which seems to be
hardly related with off-shell structure of nucleon-nucleon interaction.Comment: 8 pages ; 3 fig
Scattering of heavy charged particles on hydrogen atoms
The low energy scattering of heavy positively charged particles on hydrogen
atoms (H) are investigated by solving the Faddeev equations in configuration
space. A resonant value of the pH scattering length, a.u., in the
pp antisymmetric state was found. This large value indicates the existence of a
first excited state with a binding energy B=1.14 a.u. below the
H ground state. Several resonances for non zero angular momenta states are
predicted.Comment: 8 pages, 9 figures, contribution to International Workshop "Dynamics
and structure of critically stable quantum few-body systems" held at Les
Houches, France, October 8-13, 2001. To appear in Few-Body Physic
Small clusters of fermions
By comparing respectively the interaction between 3He atoms and the
neutron-neutron one, we examine the possibility for both fermionic systems to
form small clusters.Comment: Contributed talk to 17th International IUPAP Conference on Few-Body
Problems in Physics, Durham, North Carolina, 5-10 June 2003. Published in the
proceedings (Elsevier, 2004) pp. S106-S10
Coulomb effects in four nucleon continuum states
The Faddeev-Yakubovski equations are solved in configuration space for low
energy four-nucleon continuum states. Coulomb interaction was included into the
formalism permitting an exact description of the scattering states in
p+He and p+H systems
Low energy n-\nuc{3}{H} scattering : a novel testground for nuclear interaction
The low energy n-\nuc{3}{H} elastic cross sections near the resonance peak
are calculated by solving the 4-nucleon problem with realistic NN interactions.
Three different methods -- Alt, Grassberger and Shandas (AGS), Hyperspherical
Harmonics and Faddeev-Yakubovsky -- have been used and their respective results
are compared. We conclude on a failure of the existing NN forces to reproduce
the n-\nuc{3}{H} total cross section.Comment: To be published in Phys. Rev.
On the possibility of generating a 4-neutron resonance with a {\boldmath } isospin 3-neutron force
We consider the theoretical possibility to generate a narrow resonance in the
four neutron system as suggested by a recent experimental result. To that end,
a phenomenological three neutron force is introduced, in addition to a
realistic interaction. We inquire what should be the strength of the
force in order to generate such a resonance. The reliability of the
three-neutron force in the channel is exmined, by analyzing its
consistency with the low-lying states of H, He and Li and the
scattering.
The {\it ab initio} solution of the Schr\"{o}dinger equation is obtained
using the complex scaling method with boundary conditions appropiate to the
four-body resonances. We find that in order to generate narrow resonant
states a remarkably attractive force in the channel is required.Comment: 11 pages, 11 figures, minor change, published version, to be
published in Physical Review
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