Lambda polarization in associated K+-Lambda electro-production

The result of a feasibility study to measure the II polarization in associated K+-Lambda electro-production is presented. This measurement was performed in the experimental Hall C at Jefferson Lab. The scattered electron was detected in the HMS spectrometer, and the electro-produced kaon and the proton from the Lambda --> p pi(-) decay were both detected in the SOS spectrometer. This quantity is very sensitive to the elementary p(e,e' K)Lambda process and gives information on resonance production, and Regge exchange, among others. The result presented was measured at Q(2) = 1.50 (GeV/c)(2) and cos theta(K gamma)(CM) = 14 degrees. The limits of the Lambda polarization, with respect to the P-gamma X P-K axis, were found to be -0.21 and +0.89 with a confidence level of 68%. The result is compared to theoretical predictions based on an effective hadronic field Lagrangian model and a Regge framework model. (C) 1999 Elsevier Science B.V. All rights reserved