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arXiv · 0705.3550

Recoil polarization and beam-recoil double polarization measurement of ηelectroproduction on the proton in the region of the S_{11}(1535) resonance

H. Merkel·P. Achenbach·C. A. Ayerbe Gayoso·J. C. Bernauer·R. Böhm·D. Bosnar·B. Cheymol·M. O. Distler·L. Doria·H. Fonvieille·J. Friedrich·P. Janssens·M. Makek·U. Müller·L. Nungesser·J. Pochodzalla·M. Potokar·S. Sánchez Majos·B. S. Schlimme·S. Širca·L. Tiator·Th. Walcher·M. Weinriefer
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Abstract

The beam-recoil double polarization P_{x'}^h and P_{z'}^h and the recoil polarization P_{y'} were measured for the first time for the p(\vec{e},e'\vec{p})ηreaction at a four-momentum transfer of Q^2=0.1 GeV^2/c^2 and a center of mass production angle of θ= 120^\circ at MAMI C. With a center of mass energy range of 1500 MeV < W < 1550 MeV the region of the S_{11}(1535) and D_{13}(1520) resonance was covered. The results are discussed in the framework of a phenomenological isobar model (Eta-MAID). While P_{x'}^h and P_{z'}^h are in good agreement with the model, P_{y'} shows a significant deviation, consistent with existing photoproduction data on the polarized-target asymmetry.

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H. Merkel, P. Achenbach, C. A. Ayerbe Gayoso, J. C. Bernauer, R. Böhm, D. Bosnar, B. Cheymol, M. O. Distler, L. Doria, H. Fonvieille, J. Friedrich, P. Janssens, M. Makek, U. Müller, L. Nungesser, J. Pochodzalla, M. Potokar, S. Sánchez Majos, B. S. Schlimme, S. Širca, L. Tiator, Th. Walcher, M. Weinriefer. 2007-05-24. Recoil polarization and beam-recoil double polarization measurement of ηelectroproduction on the proton in the region of the S_{11}(1535) resonance. https://doi.org/10.1103/physrevlett.99.132301

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