4,525 research outputs found
Neutral kaon photoproduction on the deuteron
Neutral kaon photoproduction on the deuteron has been investigated by
including the final state effects and compared with the experimental data.
Comparison shows that the models used in this calculation can reproduce the
data in the channel regions fairly well but still give over
predictions in the channel. It seems that the tensor target
asymmetries are more suitable for studying the final state effects. The
extractions of the elementary photoproduction amplitude are also demonstrated.Comment: 6 pages, 6 figures, talk given by A. Salam at Fourth Asia-Pacific
Conference on Few-Body Problems in Physics 2008 (APFB08), Depok, Indonesia,
August 19-23, 200
Missing Resonances in Kaon Photoproduction on the Nucleon
New kaon photoproduction data on a proton, gamma + p --> K+ + Lambda, are
analyzed using a multipole approach. The background terms are given in terms of
gauge invariant, crossing symmetric, Born diagrams with hadronic form factors,
while the resonances are parameterized using Breit-Wigner forms. Preliminary
results suggest a number of new resonances, as predicted by many quark model
studies. A comparison between the extracted multipoles and those obtained from
KAON-MAID is presented.Comment: 10 pages, 6 figures, invited talk at the International Symposium on
Electrophotoproduction of Strangeness on Nucleons and Nuclei (SENDAI 03),
Sendai, Japan, 16-18 Jun 200
Low Densities Instability of Relativistic Mean Field Models
The effects of the symmetry energy softening of the relativistic mean field
(RMF) models on the properties of matter with neutrino trapping are
investigated. It is found that the effects are less significant than those in
the case without neutrino trapping. The weak dependence of the equation of
state on the symmetry energy is shown as the main reason of this finding. Using
different RMF models the dynamical instabilities of uniform matters, with and
without neutrino trapping, have been also studied. The interplay between the
dominant contribution of the variation of matter composition and the role of
effective masses of mesons and nucleons leads to higher critical densities for
matter with neutrino trapping. Furthermore, the predicted critical density is
insensitive to the number of trapped neutrinos as well as to the RMF model used
in the investigation. It is also found that additional nonlinear terms in the
Horowitz-Piekarewicz and Furnstahl-Serot-Tang models prevent another kind of
instability, which occurs at relatively high densities. The reason is that the
effective sigma meson mass in their models increases as a function of the
matter density.Comment: 25 pages, 10 figures, submitted to Phys. Rev.
Role of the meson in photoproduction off the deuteron
Neutral kaon photoproduction off the nucleon and deuteron has been
reinvestigated by utilizing the new experimental data on both targets. An
isobar model for elementary operator and impulse approximation for the reaction
on the deuteron have been used. The available free parameters in the elementary
model have been extracted from both elementary and deuteron data. In contrast
to the elementary reaction, fitting the deuteron data requires an inclusion of
weighting factor. The result indicates that the angular distribution of the
elementary process does not show backward peaking behavior.Comment: 4 pages, 4 figures, prepared for the Fifth Asia-Pacific Conference on
Few-Body Problems in Physics 2011 (APFB2011), Seoul, Korea, August 22-26,
201
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