Search

I give a brief overview of the exploration of baryon properties in meson photo- and electroproduction. These processes provide ample information for the study of electromagnetic couplings of baryon resonances and to search for states, yet to be discovered. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as polarized targets and the measurement of recoil polarization, provide the tools for a comprehensive nucleon resonance program. I briefly present the status of this program, prospects for the next few years, and plans for the Jefferson Lab 12 GeV upgrade. [ABSTRACT FROM AUTHOR]

A brief overview of strangeness physics with the CLAS detector at JLab is given, mainly covering the domain of nucleon resonances. Several excited states predicted by the symmetric constituent quark model may have significant couplings to the KΛ or KΣ channels. We will discuss data that are relevant in the search for such states in the strangeness channel, and give an outlook on the future prospects of the N* program at JLab with electromagnetic probes. [ABSTRACT FROM AUTHOR]

The status of the search for pentaquark baryon states is reviewed in light of new results from the first two dedicated experiments from CLAS at Jefferson Lab and of new analyses from several labs on the Θ+(1540). Evidence for and against the heavier pentaquark states, the Ξ(1862) and the $\Theta^0_c(3100)$ observed at CERN and at HERA, respectively, are also discussed. I conclude that the evidence against the latter two heavier pentaquark baryons is rapidly increasing making their existence highly questionable. I also conclude that the evidence for the Θ+ state has significantly eroded with the recent CLAS results, but still leaves room for a state with an intrinsic width of Γ < 0.5 MeV. New evidence in support of a low mass pentaquark state from various experiments will be discussed as well. [ABSTRACT FROM AUTHOR]

Recent results on the study of the electromagnetic structure of nucleon resonances, the spin structure of protons and neutrons at small and intermediate photon virtuality, and the search for exotic pentaquark baryons are presented. [ABSTRACT FROM AUTHOR]

Several experiments at Jefferson Lab Hall A have used a polarized ³He target for studying the spin structure of the neutron. Measurements have been published for the neutron magnetic form factor, and are being published for the extended Gerasimov-Drell-Hearn sum rule. The A[sub 1, sup n] asymmetry and the g[sub 2, sup n] structure function have been measured above the resonance region. Further measurements in the resonance region will be performed in the near future. [ABSTRACT FROM AUTHOR]