Recoil polarization and beam-recoil double polarization measurement of eta electroproduction on the proton in the region of the S11(1535) resonance.
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(e,e'p)eta reaction at a four-momentum transfer of Q(2) = 0.1 GeV(2)/c(2) and a center of mass production angle of theta = 120 degrees at the Mainz Microtron MAMI-C. With a center of mass energy range of 1500 MeV<W<1550 MeV the region of the S11(1535) and D13(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.
Merkel
H
H
Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany. merkel@kph.uni-mainz.de
Achenbach
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P
Ayerbe Gayoso
C
C
Bernauer
J C
JC
Böhm
R
R
Bosnar
D
D
Cheymol
B
B
Distler
M O
MO
Doria
L
L
Fonvieille
H
H
Friedrich
J
J
Janssens
P
P
Makek
M
M
Müller
U
U
Nungesser
L
L
Pochodzalla
J
J
Potokar
M
M
Sánchez Majos
S
S
Schlimme
B S
BS
Sirca
S
S
Tiator
L
L
Walcher
Th
T
Weinriefer
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M