Quasifree Lambda, Sigma0, and Sigma− electroproduction from 1,2H, 3,4He and carbon

A comprehensive study of kaon electroproduction on light nuclei has been conducted in Hall C of the Thomas Jefferson National Accelerator Facility by the E91-016 collaboration. Data were obtained using electron beams of 3.245 GeV impinging on special high density cryogenic targets of 1,2H, 3,4He, as well as on a solid carbon target. Specifically, the measurements on 3,4He are the first performed. Previously, the observation of hypernuclear bound states was discussed [1]. This presentation will give the final results of the data analysis, focussing on the quasifree production cross sections for the Lambda and Sigma hyperons for the various target nuclei [2]. We also derive effective proton numbers from our data and compare these numbers with model calculations. Deviations may indicate possible in-medium modifications of the kaon electroproduction mechanism.

[1] F. Dohrmann et al [E91016 collab.] Phys. Rev. Lett. 93 (2004) 242501
[2] F. Dohrmann et al [E91016 collab.] Phys. Rev. C 76 (2007) 054004