DOI 10.1007/s100529900067
Odderon and photon exchange in electroproduction of pseudoscalar mesons
E.R. Berger1 - A. Donnachie2 - H.G. Dosch1 - W. Kilian3 - O. Nachtmann1 - M. Rueter4
1 Institut für Theoretische Physik der Universität Heidelberg,
Philosophenweg 16, D-69120 Heidelberg, Germany
(e-mail: e.berger, h.g.dosch, o.nachtmann@thphys.uni-heidelberg.de)
2 TH Division, CERN
(e-mail: ad@a3.ph.man.ac.uk)
3 Institut für Theoretische Teilchenphysik, Universität Karlsruhe,
D-76128 Karlsruhe, Germany
(e-mail: kilian@particle.physik.uni-karlsruhe.de)
4 School of Physics and Astronomy, Department of High Energy Physics,
Tel Aviv University, 69978 Tel Aviv, Israel
(e-mail: rueter@post.tau.ac.il)
Received: 2 February 1999 / Revised version: 22 March 1999 / Published online: 28 May 1999
Abstract
We investigate the reaction
where PS denotes a pseudoscalar meson
,
,
, or
and X either a proton or resonance or continuum state
into which the proton can go by diffractive
excitation. At high energies photon and odderon exchange
contribute to the reaction. The photon exchange contribution
is evaluated exactly using data for the total virtual
photon-proton absorption cross section. The odderon exchange
contribution is calculated in nonperturbative QCD, using
functional integral techniques and the model of the stochastic
vacuum. For the proton we assume a quark-diquark
structure as suggested by the
small odderon amplitude in
and
forward scattering. We show that odderon exchange leads to
a much larger inelastic than elastic PS production cross section.
Observation of our reaction at HERA would establish the
soft odderon as an exchange object on an equal footing with the soft
pomeron and would give us valuable insight into both the
nucleon structure and the mechanism of high energy diffractive
scattering.
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