Measurement of the recoil polarization in the p(e-->, e'p-->)pi(0) reaction at the Delta(1232) resonance.
The recoil proton polarization has been measured in the p(e-->,e'p-->)pi(0) reaction in parallel kinematics around W = 1232 MeV, Q2 = 0.121 (GeV/c)2, and epsilon = 0.718 using the polarized cw electron beam of the Mainz Microtron. All three proton polarization components, Px/P(e) = (-11.4+/-1.3+/-1.4)%, P(y) = (-43.1+/-1.3+/-2.2)%, and P(z)/P(e) = (56.2+/-1.5+/-2.6)%, could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio, CMR = (-6.4+/-0.7(stat)+/-0.8(syst))%, was determined from Px in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal-to-transverse response is discussed.
Pospischil
T
T
Institut für Kernphysik, Universität Mainz, Germany.
Bartsch
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Baumann
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Bermuth
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Böhm
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Bohinc
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Derber
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Ding
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Distler
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Drechsel
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Elsner
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Ewald
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Friedrich
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Friedrich
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Geiges
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Hedicke
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Jennewein
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Kahrau
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Kamalov
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Klein
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Krygier
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Lac
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Liesenfeld
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McIntyre
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Merkel
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Merle
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Müller
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Neuhausen
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Potokar
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Ransome
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Rohe
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Rosner
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Schmieden
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Seimetz
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Sirca
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Sick
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Süle
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Tiator
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Wagner
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Walcher
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Warren
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Weis
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