Cross sections and Rosenbluth separations in H1(e,e′K +)Λ up to Q2=2.35GeV2

Abstract

The kaon electroproduction reaction H1(e,e′K +)Λ was studied as a function of the virtual-photon four-momentum, Q2, total energy, W, and momentum transfer, t, for different values of the virtual-photon polarization parameter. Data were taken at electron beam energies ranging from 3.40 to 5.75GeV. The center of mass cross section was determined for twenty-one kinematics corresponding to Q2 of 1.90 and 2.35GeV2, and the longitudinal, σL, and transverse, σT, cross sections were separated using the Rosenbluth technique at fixed W and t. The separated cross sections reveal a flat energy dependence at forward kaon angles not satisfactorily described by existing electroproduction models. Influence of the kaon pole on the cross sections was investigated by adopting an off-shell form factor in the Regge model, which better describes the observed energy dependence of σT and σL. © 2010 The American Physical Society.