https://doi.org/10.1140/epja/i2012-12014-9
Regular Article - Experimental Physics
Exclusive electroproduction of K+Λ and K+Σ0 final states at Q2 = 0.030–0.055 (GeV/c)2
1
Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz, Germany
2
Helmholtz Center for Heavy Ion Research, GSI, Darmstadt, Germany
3
Department of Physics, University of Zagreb, Zagreb, Croatia
4
Nuclear Physics Institute, Řež near Prague, Prague, Czech Republic
5
University of Ljubljana and Jožef Stefan Institute, Ljubljana, Slovenia
* e-mail: patrick@kph.uni-mainz.de
Received:
9
November
2011
Revised:
2
January
2012
Accepted:
27
January
2012
Published online:
10
February
2012
Cross-section measurements of the exclusive p(e, e′K +)Λ, Σ 0electroproduction reactions have been performed at the Mainz Microtron MAMI in the A1 spectrometer facility using for the first time the KAOS spectrometer for kaon detection. These processes were studied in a kinematical region not covered by any previous experiment. The nucleon was probed in its third-resonance region with virtual photons of low four-momenta, Q 2 = 0.030–0.055 (GeV/c)2. The MAMI data indicate a smooth transition in Q2 from photoproduction to electroproduction cross-sections. Comparison with predictions of effective Lagrangian models based on the isobar approach reveal that strong longitudinal couplings of the virtual photon to the N* resonances can be excluded from these models. Modern isobar and Regge-plus-resonance models are in agreement with the data.
© SIF, Springer-Verlag Berlin Heidelberg, 2012
