Cross sections and Rosenbluth separations in 1H(e, e'K+)Lambda up to Q2=2.35 GeV2

TL;DR

This study measures the cross sections for kaon electroproduction from protons at various energies and momentum transfers, revealing discrepancies with existing models and exploring the kaon pole's influence using a Regge model with an off-shell form factor.

Contribution

First detailed Rosenbluth separation of longitudinal and transverse cross sections in kaon electroproduction up to Q2=2.35 GeV2, highlighting model limitations and the role of the kaon pole.

Findings

Cross sections show flat energy dependence at forward angles.

Existing models do not fully describe the data.

Off-shell Regge model improves data description.

Abstract

The kaon electroproduction reaction 1H(e,e'K+)Lambda 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 5.75 GeV. The center of mass cross section was determined for 21 kinematics corresponding to Q2 of 1.90 and 2.35 GeV2 and the longitudinal, sigmaL, and transverse, sigmaT, 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 sigmaT and sigmaL.