First Experiment on Spectroscopy of Lambda-Hypernuclei by Electroproduction at Jlab

The first experiment in Lambda-hypernuclear spectroscopy using the high precision electron beam at Jefferson laboratory (Jlab) has been carried out. The hypernuclear spectrometer system (HNSS) was used to measure spectra from the {sup 12}C(e, e{prime}K{sup +}){sup 12}{sub {Lambda}}B reaction with sub-1 MeV resolution, the best energy resolution obtained thus far in hypernuclear spectroscopy with magnetic spectrometers. This paper describes the HNSS and the preliminary results for the {sup 12}{sub {Lambda}}B system. The experimental spectrum is consistent with the expected strong spin-flip excitations of unnatural parity states. A program of hypernuclear physics experiments is planned for the future with much higher yield and even better energy resolution.