High resolution spectroscopic study of Be-10(Lambda)

Spectroscopy of a Be-10(Lambda) hypernucleus was carried out at JLab Hall C using the (e, e' K+) reaction. A new magnetic spectrometer system (SPL+ HES+ HKS), specifically designed for high resolution hypernuclear spectroscopy, was used to obtain an energy spectrum with a resolution of similar to 0.78 MeV (FWHM). The well-calibrated spectrometer system of the present experiment using p(e, e' K+)Lambda, Sigma(0) reactions allowed us to determine the energy levels; and the binding energy of the ground-state peak (mixture of 1(-) and 2(-) states) was found to be B-Lambda = 8.55 +/- 0.07(stat.) +/- 0.11(sys.) MeV. The result indicates that the ground-state energy is shallower than that of an emulsion study by about 0.5 MeV which provides valuable experimental information on the charge symmetry breaking effect in the Lambda N interaction.