22 research outputs found
Bremsstrahlung of 350--450 MeV protons as a tool to study interaction off-shell
The bremsstrahlung cross section is calculated within the
method of coordinate space representation. It is shown that in the beam energy
range of 350--450~MeV a deep attractive NN-potential with forbidden states
(Moscow potential) and realistic meson exchange potentials (MEP) give rise to
the cross sections that differ essentially in shape: the cross sections nearly
coincide in the minima but differ by a factor of 5 approximately in the maxima.
Therefore, the reaction at energies 350--450~Mev can be
used to study interaction off-shell and to discriminate experimentally
between MEP and Moscow potential.Comment: 5 pages, latex, 4 PS figures. Talk presented by Andrey Shirokov at
the International Conference on Quark Lepton Nuclear Physics ``QULEN97'', May
20-23, 1997, Osaka, Japan; to be published in Nucl. Phys.
Quasi-elastic knockout of pions and kaons from nucleons by high-energy electrons and quark microscopy of "soft" meson degrees of freedom in the nucleon
Electro-production of pions and kaons at the kinematics of quasi-elastic
knockout (which is well known in the physics of atomic nucleus and corresponds
to the -pole diagram) is proposed for obtaining their momentum distribution
(MD) in various channels of virtual decay , , ,
, , and , , . It is a powerful tool
for investigation of a quark microscopic picture of the meson cloud in the
nucleon. A model of scalar () fluctuation in the non-trivial
QCD vacuum is used to calculate pion and kaon momentum distributions (MD) in
these channels.Comment: 31 pages, 11 figures, submitted to Nucl.Phys.
Charge Form Factor and Cluster Structure of Li Nucleus
The charge form factor of Li nucleus is considered on the basis of its
cluster structure. The charge density of Li is presented as a
superposition of two terms. One of them is a folded density and the second one
is a sum of He and the deuteron densities. Using the available
experimental data for He and deuteron charge form factors, a good
agreement of the calculations within the suggested scheme is obtained with the
experimental data for the charge form factor of Li, including those in
the region of large transferred momenta.Comment: 12 pages 5 figure
NN Core Interactions and Differential Cross Sections from One Gluon Exchange
We derive nonstrange baryon-baryon scattering amplitudes in the
nonrelativistic quark model using the ``quark Born diagram" formalism. This
approach describes the scattering as a single interaction, here the
one-gluon-exchange (OGE) spin-spin term followed by constituent interchange,
with external nonrelativistic baryon wavefunctions attached to the scattering
diagrams to incorporate higher-twist wavefunction effects. The short-range
repulsive core in the NN interaction has previously been attributed to this
spin-spin interaction in the literature; we find that these perturbative
constituent-interchange diagrams do indeed predict repulsive interactions in
all I,S channels of the nucleon-nucleon system, and we compare our results for
the equivalent short-range potentials to the core potentials found by other
authors using nonperturbative methods. We also apply our perturbative
techniques to the N and systems: Some
channels are found to have attractive core potentials and may accommodate
``molecular" bound states near threshold. Finally we use our Born formalism to
calculate the NN differential cross section, which we compare with experimental
results for unpolarised proton-proton elastic scattering. We find that several
familiar features of the experimental differential cross section are reproduced
by our Born-order result.Comment: 27 pages, figures available from the authors, revtex, CEBAF-TH-93-04,
MIT-CTP-2187, ORNL-CCIP-93-0