2,795 research outputs found
New Results on the Electroproduction Cross Sections off Protons
In these proceedings we present preliminary
electroproduction cross sections off protons in the kinematical area of 1.4 GeV
1.8 GeV and 0.4 GeV GeV. Our results extend
the kinematical coverage for this exclusive channel with respect to previous
measurements. Furthermore, the electroproduction cross
sections were obtained for -bins of much smaller size. The future analysis
of this data within the framework of the JLAB-MSU reaction model (JM) will
considerably improve our knowledge on the evolution of the transition
electrocouplings, in particular for the resonances with masses
above 1.6 GeV.Comment: Will be published in proceedings of NSTAR 2011 conference. 4 pages, 4
figure
Electroexcitation of nucleon resonances at Q^2=0.65 GeV/c^2 from a combined analysis of single- and double-pion electroproduction data
Data on single- and double-charged pion electroproduction off protons are
successfully described in the second and third nucleon resonance regions with
common N* photocouplings. The analysis was carried out using separate isobar
models for both reactions. From the combined analysis of two exclusive
channels, the gamma* p --> N*+ helicity amplitudes are obtained for the
resonances P11(1440), D13(1520), S31(1620), S11(1650), F15(1680), D33(1700),
D13(1700), and P13(1720) at Q2=0.65 GeV/c^2.Comment: 12 pages, 12 figures (eps), Published in PHYSICAL REVIEW C 72, 045201
(2005
Electroproduction of pπ+π− off protons at 0.2
This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep→e′pπ+π−. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.
Model Analysis of the Electroproduction Reaction on the Proton
Recent CLAS data on the electroproduction off protons at
1.3W1.57 GeV and 0.250.6 GeV have been analyzed using
a meson-baryon phenomenological model. By fitting nine 1-fold differential
cross section data for each and bin, the charged double pion
electroproduction mechanisms are identified from their manifestations in the
observables. We have extracted the cross sections from amplitudes of each of
the considered isobar channels as well as from their coherent sum. We also
obtained non-resonant partial wave amplitudes of all contributing isobar
channels which could be useful for advancing a complete coupled-channel
analysis of all meson electroproduction data.Comment: Experiment Numbers: E93-006, E94-005 Group: Hall
Phenomenological analysis of the CLAS data on double charged pion photo and electro- production
First comprehensive data on the evolution of nucleon resonance photocouplings
with photon virtuality Q^2 are presented for excited proton states in the mass
range from 1.4 to 2.0 GeV. N^* photocouplings were determined in
phenomenological analysis of CLAS data on 2 pi photo and electroproduction
within the framework of the JLAB-MSU phenomenological model.Comment: 10 pages, 7 figures (encapsulated postscript
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