Experimental techniques and performance of Λ-hypernuclear spectroscopy with the (e,e′K+) reaction

Abstract The missing-mass spectroscopy of Λ hypernuclei via the ( e , e ′ K + ) reaction has been developed through experiments at JLab Halls A and C in the last two decades. For the latest experiment, E05-115 in Hall C, we developed a new spectrometer system consisting of the HKS and HES; resulting in the best energy resolution ( Δ E ≃ 0 . 5 -MeV FWHM) and B Λ accuracy ( Δ B Λ ≤ 0 . 2 MeV ) in Λ -hypernuclear reaction spectroscopy. This paper describes the characteristics of the ( e , e ′ K + ) reaction compared to other reactions and experimental methods. In addition, the experimental apparatus, some of the important analyses such as the semi-automated calibration of absolute energy scale, and the performance achieved in E05-115 are presented.