3,376 research outputs found
A new screening function for Coulomb renormalization
We introduce a new screening function which is useful for the few-body
Coulomb scattering problem in ``screening and renormalization'' scheme. The new
renormalization phase factor of the screening function is analytically shown.
The Yukawa type of the screening potential has been used in several decades, we
modify it to make more useful. As a concrete example, we compare the
proton-proton scattering phase shifts calculated from these potentials. The
numerical results document that high precision calculations of the
renormalization are performed by the new screening function.Comment: 4 pages, 8 figure
Solution of the Faddeev-Yakubovsky equations using realistic NN and 3N interaction
We solve the Faddeev-Yakubovsky equations for 3N and 4N bound states based on
the most modern realistic nucleon-nucleon interactions. We include different
realistic 3N forces. It is shown that all 3N force models can remove the
underbinding of the triton and alpha-particle which one obtains with existing
NN interactions. The agreement of theoretical predictions and the experimental
binding energy is quite good and there is little room left for the action of
four-nucleon forces in the alpha-particle. The effect of 3N forces on the wave
function is investigated.Comment: 4 pages, to appear in the proceedings of the "European Few-Body
Conference", Evora 200
Relativistic effects in neutron-deuteron elastic scattering
We solved the three-nucleon Faddeev equation including relativistic features
such as relativistic kinematics, boost effects and Wigner spin rotations. As
dynamical input a relativistic nucleon-nucleon interaction exactly on-shell
equivalent to the AV18 potential has been used. The effects of Wigner rotations
for elastic scattering observables were found to be small. The boost effects
are significant at higher energies.They diminish the transition matrix elements
at higher energies and lead in spite of the increased relativistic phase-space
factor as compared to the nonrelativistic one to rather small effects in the
cross section, which are mostly restricted to the backward angles.Comment: 27 pages, 5 Postscript figure
Complex Energy Method for Scattering Processes
A method for solving few-body scattering equations is proposed and examined.
The solution of the scattering equations at complex energies is analytically
continued to get scattering T-matrix with real positive energy. Numerical
examples document that the method works well for two-nucleon scattering and
three-nucleon scattering, if the set of complex energies is properly chosen.Comment: 6 pages, no figures, resubmitted to Prog. Theor. Phy
Realistic two-nucleon potentials for the relativistic two-nucleon Schroedinger equation
The potentials in the nonrelativistic (relativistic) nucleon-nucleon
(NN) Schroedingerequation are related by a quadratic equation. That equation is
numerically solved, thus providing phase equivalent v- potentials related for
instance to the high precision NN potentials, which are adjusted to NN phase
shift and mixing parameters in a nonrelativistic Schroedinger equation. The
relativistic NN potentials embedded in a three-nucleon (3N)system for total NN
momenta different from zero are also constructed in a numerically precise
manner. They enter into the relativistic interacting 3N mass operator, which is
needed for relativistic 3N calculations for bound and scattering states.Comment: 6 pages, 4figures, 2 tables; typos adde
A New Look into the Partial Wave Decomposition of Three-Nucleon Forces
We demonstrate that the partial wave decomposition of three-nucleon forces
used up to now in momentum space has to be necessarily unstable at high partial
waves. This does not affect the applications performed up to now, which were
restricted to low partial waves. We present a new way to perform the partial
wave decomposition which is free of that defect. This is exemplified for the
most often used -exchange Tuscon-Melbourne three-nucleon force. For the
lower partial waves the results of the old method are reproduced.Comment: 38 pages in REVTeX, 4 figures in PiCTe
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