DATE: |
2009-04-20 15:30 - 15:30 |
PLACE: |
Kenkyu Honkan Rm. 321 |
TITLE: |
phi-meson photoproduction off proton with coupled channel approach |
CONTACT: |
YASUI Shigehiro / yasuis AT post.kek.jp |
LANGUAGE: |
Japanese |
ABSTRACT: |
Recently, several photon facilities have been reporting interesting results in the energy region of the strangeness (sar{s}) production,
including the pentaquarks, Lambda resonances and phi-meson.
Among those, phi-photoproduction has a unique feature such that the gluon dynamics (Pomeron contribution) dominates
because the OZI rule suppress hadron dynamics due to the sar{s} dominance of phi-meson.
Previously, Pomeron and meson exchange model successfully reproduced
differential cross sections and spin observables in the forward angle region.
In 2005, LEPS group, however, has observed a peak structure near the threshold.
It is known that such a structure is difficult to be explained within this model.
In order to reproduce the structure we investigate coupled channel effects in the phi-meson photoprduction.
Especially we pay attention to the following two aspects.
One is an on-shell kaon exchange effect in the transition amplitude phi N o K Lambda(1520), which is kinematically allowed,
in the energy region where a peak structure has been observed in phi-photoproduciton.
We also discuss the possibility of a nucleon resonance which may contain large sars components.
In this seminar I discuss results of these effects. |
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