1,165 research outputs found
ESC NN-Potentials in Momentum Space. I. PS-PS Exchange Potentials
A momentum space representation is derived for the Nijmegen
Extended-Soft-Core (ESC) interactions. The partial wave projection of this
representation is carried through, in principle for Two-Meson-Exchange (TME) in
general. Explicit results for the momentum space partial wave NN-potentials
from PS-PS-Exchange are given.Comment: 23 pages, 2 PostScript figures, revtex
ESC NN-Potentials in Momentum Space. II. Meson-Pair Exchange Potentials
The partial wave projection of the Nijmegen soft-core potential model for
Meson-Pair-Exchange (MPE) for NN-scattering in momentum space is presented.
Here, nucleon-nucleon momentum space MPE-potentials are NN-interactions where
either one or both nucleons contains a meson-pair vertex. Dynamically, the
meson-pair vertices can be viewed as describing in an effective way (part of)
the effects of heavy-meson exchange and meson-nucleon resonances. From the
point of view of ``duality,'' these two kinds of contribution are roughly
equivalent. Part of the MPE-vertices can be found in the chiral-invariant
phenomenological Lagrangians that have a basis in spontaneous broken chiral
symmetry. It is shown that the MPE-interactions are a very important component
of the nuclear force, which indeed enables a very succesful description of the
low and medium energy NN-data. Here we present a precise fit to the NN-data
with the extended-soft-core (ESC) model containing OBE-, PS-PS-, and
MPE-potentials. An excellent description of the NN-data for
MeV is presented and discussed. Phase shifts are given and a is reached.Comment: 27 pages, 5 PostScript figures, revtex
Pion-Nucleon Scattering in Kadyshevsky Formalism: II Baryon Exchange Sector
In this paper, which is the second part in a series of two, we construct tree
level baryon exchange and resonance amplitudes for / -scattering in
the framework of the Kadyshevsky formalism. We use this formalism to formally
implement absolute pair suppression, where we make use of the method of
Takahashi and Umezawa. The resulting amplitudes are Lorentz invariant and
causal. We continue studying the frame dependence of the Kadyshevsky integral
equation using the method of Gross and Jackiw. The invariant amplitudes,
including those for meson exchange, are linked to the phase-shifts using the
partial wave basis.Comment: 49 page
Extended-soft-core Baryon-Baryon Model II. Hyperon-Nucleon Interaction
The YN results are presented from the Extended-soft-core (ESC) interactions.
They consist of local- and non-local-potentials due to (i) One-boson-exchange
(OBE), with pseudoscalar-, vector-, scalar-, and axial-vector-nonets, (ii)
Diffractive exchanges, (iii) Two-pseudoscalar exchange, and (iv)
Meson-pair-exchange (MPE). This model, called ESC04, describes NN and YN in a
unified way using broken flavor SU(3)-symmetry. Novel ingredients are the
inclusion of (i) the axial-vector-mesons, (ii) a zero in the scalar- and
axial-vector meson form factors. We describe simultaneous fits to the NN- and
YN-data, using four options in the ESC-model. Very good fits were obtained.
G-matrix calculations with these four options are also reported. The obtained
well depths (U_\Lambda, U_\Sigma, U_\Xi) reveal distinct features of ESC04a-d.
The \Lambda\Lambda-interactions are demonstrated to be consistent with the
observed data of_{\Lambda\Lambda}^6He. The possible three-body effects are
investigated by considering phenomenologically the changes of the vector-meson
masses in a nuclear medium.Comment: preprint vesion 66 pages, two-column version 27 pages, 17 figure
Fully double-logarithm-resummed cross sections
We calculate the complete double logarithmic contribution to cross sections
for semi-inclusive hadron production in the modified minimal-subtraction scheme
by applying dimensional regularization to the double logarithm approximation.
The full double logarithmic contribution to the coefficient functions for
inclusive hadron production in electron-positron annihilation is obtained in
this scheme for the first time. Our result agrees with all fixed order results
in the literature, which extend to next-next-to-leading order.Comment: To appear in Nuclear Physics
Antiproton-proton partial-wave analysis below 925 MeV/c
A partial-wave analysis of all antiproton-proton scattering data below 925
MeV/c antiproton laboratory momentum is presented. The method used is adapted
from the Nijmegen phase-shift analyses of pp and np scattering data. The
Nijmegen 1993 antiproton-proton database, consisting of 3646 antiproton-proton
scattering data, is presented and discussed. The best fit to this database
results in chi^2_min/Ndata = 1.043. The pseudovector coupling constant of the
charged pion to nucleons is determined to be (f_c)^2 = 0.0732(11) at the pion
pole, where the error is statistical.Comment: Report THEF-NYM 93.02 42 pages REVTeX, 7 separate postscript figures
appended. Accepted for publication in Phys. Rev.
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