First measurement of the helicity-dependent (gamma)over-right-arrow(p)over-right-arrow -> p eta differential cross-section

ISSN
1434-601X
1434-6001
Date Issued
2003
Author(s)
Ahrens, J.
Altieri, S.
Annand, JRM
Anton, G.
Arends, H. J.
Aulenbacher, K.
Beck, R.
Bradtke, C.
Braghieri, A.
d'Hose, N.
Drechsel, D.
Dutz, H.
Goertz, S.
Grabmayr, P.
Hansen, K.
Harmsen, J.
von Harrach, D.
Hasegawa, S.
Hasegawa, T.
Heid, E.
Helbing, Krister
Holvoet, H.
van Hoorebeke, L.
Horikawa, N.
Iwata, T.
Jennewein, P.
Kageya, T.
Kiel, B.
Klein, F.
Kondratiev, R.
Kossert, K.
Krimmer, J.
Lang, M.
Lannoy, B.
Leukel, R.
Lisin, V.
Matsuda, T.
McGeorge, J. C.
Meier, A.
Menze, D.
Meyer, Werner
Michel, Tanja Maria
Naumann, J.
Panzeri, A.
Pedroni, P.
Pinelli, T.
Preobrajenski, I.
Radtke, E.
Reichert, E.
Reicherz, G.
Rohlof, C.
Rosner, G.
Ryckbosch, D.
Schoch, B.
Schumacher, M.
Seitz, Bjoern
Speckner, T.
Takabayashi, N.
Tamas, Gabor
Thomas, Andy
van de Vyver, R.
Wakai, A.
Weihofen, W.
Wissmann, F.
Zapadtka, F.
Zeitler, G.
DOI
10.1140/epja/i2002-10153-2
Abstract
The helicity dependence of the (gamma) over right arrow(p) over right arrow -+ peta reaction has been measured for the first time at a center-of-mass angle theta(eta) = 70degrees in the photon energy range from 780 MeV to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam. and a longitudinally polarized frozen-spin target. The helicity 3/2 cross-section is found to be small and the results for helicity 1/2 agree with predictions from the MAID analysis.