2,639 research outputs found
Evidence for the J^p=1/2^+ narrow state at 1650 MeV in the photoproduction of KLambda
We have investigated the existence of the J^p=1/2^+ narrow resonance
predicted by the chiral soliton model by utilizing the kaon photoproduction
process gamma + p --> K^+ + Lambda. For this purpose we have constructed two
phenomenological models based on our previous effective Lagrangian model, which
are able to describe kaon photoproduction from threshold up to W = 1730 MeV. By
varying the mass (width) of an inserted P_{11} resonance from 1620 to 1730 MeV
(0.1 to 1 MeV and 1 to 10 MeV) a number of fits has been performed in order to
search for the resonance mass. Our result indicates that the most promising
candidate mass (width) of this resonance is 1650 MeV (5 MeV). Although our
calculation does not exclude the possibility of narrow resonances with masses
of 1680, 1700 and 1720 MeV, the mass of 1650 MeV is obtained for all
phenomenological models used in this investigation. Variations of the resonance
width and branching ratio are found to have a mild effect on the
chi^2. The possibility that the obtained result originates from other resonance
states is also discussed.Comment: 27 pages, 19 figures, submitted to Phys. Rev.
Electromagnetic K+ production on the deuteron with hyperon recoil polarization
Photo- and electroproduction processes of K+ on the deuteron are investigated
theoretically. Modern hyperon-nucleon forces as well as an updated kaon
production operator on the nucleon are used. Sizable effects of the
hyperon-nucleon final state interaction are seen in various observables.
Especially the photoproduction double polarization observable C_z is shown to
provide a handle to distinguish different hyperon-nucleon force models.Comment: 4 pages, 7 eps-figures, talk given at the VII International
Conference on Hypernuclear and Strange Particle Physics, Torino, Italy,
October 23-27, 2000, to appear in the proceedings (Nucl. Phys. A
Kaon photoproduction on the nucleon: overview of some applications
Some applications of the elementary kaon photoproduction process are
discussed: the investigation of missing resonances in the p(gamma,K+)Lambda
channel, the role of the P_{13}(1720) state in the p(gamma,K0)Sigma+ channel,
and the calculation of the Gerasimov-Drell-Hearn sum rule. For the latter, we
present an extension of our previous study to higher energies.Comment: 3 pages, contribution to FB2000 (Taiwan) March 2000, to be published
in Nucl. Phys.
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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