[Frost] Abstract

[Daniel Watts]

Hi All,

Please find below an abstract for a talk I plan to give at Hadron 
Structure '11 in the Slovak Republic at the end of June. Any comments or 
suggestions would be appreciated!

Many thanks,
Dan



Talk title: Meson photoproduction from the nucleon at CLAS

There is an extensive programme of measurements exploiting the CLAS 
detector at Jefferson Lab to obtain high quality measurements of meson 
photoproduction reactions from the nucleon.  The central aim of the 
measurement programme is to better establish the spectrum and properties 
of nucleon resonances, information which provides valuable information 
on the dynamics and interactions of the nucleons constituents.
Theoretical predictions of the nucleon resonance spectrum can be 
obtained from a range of approaches,  including constituent quark models 
and Lattice QCD. Despite the recent exciting advances in theory the 
properties and existence of many nucleon resonances remain poorly 
established experimentally. There are many resonances predicted by the 
theoretical models which have not been found in analyses of experimental 
data. It is not currently established if this is due to the poor quality 
of the experimental data or shortcomings in the theoretical approaches.

The new JLab meson photoproduction data will provide new, quality data 
to the world data set of meson photoproduction. The new data has been 
obtained with linearly and circularly polarised photon beams and with a 
polarised frozen spin nucleon target (FROST), giving access to many 
single- and double- polarisation observables in meson photoproduction. 
The measurements cover a large fraction of the resonance region with a  
close to complete kinematic coverage for the produced mesons. The new 
data will enable a more reliable determination of the reaction 
amplitudes, improving the accuracy in the extraction of the resonance 
spectrum and its properties. Preliminary data and analyses from the 
programme will be presented in the talk.

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