Measurement of strange quark contributions to the vector form factors of the proton at Q2 = 0.22 (GeV / c)2.
A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q;{2} = 0.22 (Ge V / c);{2} is reported here. The measured asymmetry is A_{LR} = (-17.23 +/- 0.82_{stat} +/- 0.89_{syst}) x 10;{-6}. The standard model prediction assuming no strangeness is A_{0} = (-15.87 +/- 1.22) x 10;{-6}. In combination with previous results from measurements at forward angles, it is possible to disentangle for the first time the strange form factors at this momentum transfer, G_{E};{s} = 0.050 +/- 0.038 +/- 0.019 and G_{M};{s} = -0.14 +/- 0.11 +/- 0.11.
Baunack
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Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany. baunack@kph.uni-mainz.de
Aulenbacher
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Balaguer Ríos
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Capozza
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Diefenbach
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Gläser
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von Harrach
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Imai
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Kabuss
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Kothe
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Lee
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Merkel
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Mora Espí
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Müller
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Schilling
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Stephan
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Weinrich
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Arvieux
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El-Yakoubi
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Frascaria
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Kunne
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Maas
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Morlet
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Ong
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van de Wiele
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Kowalski
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Prok
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Taylor
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