FIZIKA B 8 (1999) 1, 71-80

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THE SEARCH FOR MISSING BARYONS WITH A BEAM OF LINEARLY-POLARIZED PHOTONS

PHILIP L. COLE

University of Texas at El Paso, El Paso, TX 79968, USA
E-mail: cole@jlab.org ,   fax: (915) 845-5447

Received 14 January 1999; Accepted 7 June 1999

The photoproduction of w and r mesons from protons with a beam of linearly-polarized photons will be used to decouple baryon resonance production from t-exchange processes in the center-of-mass energy regime of 1.72 to 2.24 GeV at Hall B of Jefferson Lab. Both the wN and rN channels are expected to be a significant branch for baryon resonances. t-channel exchange contributions can only be disentangled by the use of a linearly-polarized photon beam. The measurement will employ a linearly-polarized beam of photons, produced by the approved Coherent Bremsstrahlung Facility, to measure the beam asymmetry as well as the spin density matrix elements of the decay spin-0 mesons of the parent vector meson. The spin density matrix elements and polarization asymmetry of the vector meson decay will be extracted as functions of the vector meson production angle qcm and the center-of-mass energy s in the center-of-mass frame. These measurements will expedite the search for baryon resonance contributions, and furthermore, will yield new physics information on diffractive, t- and u-channel processes. Our approved experiments will increase the world's data set by three orders of magnitude.

PACS numbers: 13.60.Rj, 14.20.Gk
UDC 539.126

Keywords:baryon resonances,photoproduction, w and r mesons, linearly-polarized photons, t- and u-channel processes

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