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RESEARCH PRODUCT

Hypernuclear Spectroscopy with Electron Beams

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A Λ-hyperon bound to a nuclear core, forming a hypernuclei, is a unique probe of the interior of hadronic many-body systems. Only recently, the spectroscopy of Λ-hypernuclei with electron beams was realized. Today, two places worldwide offer the possibility to study hypernuclei with high intensity continuous electron beams: MAMI at Mainz, Germany, and Jefferson Lab (JLab), Virginia. At least two different techniques exist for such studies: reaction spectroscopy, which requires two high-resolution spectrometers, one for kaons and one for the scattered electrons, and decay particle spectroscopy of hyperfragments. In the latter case a strangeness tagger in forward direction is of great advantage to reduce the background in the pion spectrum. In Mainz, the first hypernuclei experiments on pion decay spectroscopy to be performed with the dedicated kaon spectrometer KAOS as strangeness tagger are scheduled for Summer 2011. At JLab, hypernuclear reaction spectroscopy with electron beams was pioneered in the the year 2000, followed by a decade of activities that peaked with the third generation experiment E05-115 in Hall C and the experiment E94-107 in Hall A. The spectroscopy of hypernuclei with electron beams is now an indispensable part of strangeness nuclear physics and the established co-operation between the two operating electron beam facilities will further stimulate the field.