Spectroscopic study of hypernuclei via (e,e$'$K$^+$) reaction

A new hypernuclear spectroscopy experiment by the (e,e$'$K$^+$) reaction will be carried out in June 2005 at Hall C, Jefferson Lab (E01-011). In order to improve the successful pioneering Jlab E89-009 experiment, we introduce a newly designed high resolution and large solid angle spectrometer (HKS) for the kaon arm, and employ ``Tilt method'' for the electron arm. In the ``tilt method,'' the electron spectrometer is vertically tilted by $\sim$8 degrees to reduce drastically the background electrons originating from Bremsstrahlung and M\o ller process. By adopting the new setup, we expected to : 1) increase hypernuclear yield by 50 times with higher beam current ($\sim$30 $\mu$A) and thicker target($\sim$100 mg/cm${}^2$), 2) improve to hypernuclear mass resolution twice better($\sim$400 keV[FWHM]). Under such condition, we plan to measure hypernuclear spectra for higher $Z$ targets {\it i.e.} ${}^{28}$Si, ${}^{51}$V and ${}^{89}$Y. We investigate $\Lambda$ single particle behavior deep inside the nucleus and try to understand the nature of $\Lambda$N interaction comparing with ordinary nuclei. In this report, the analysis procedure for kaon identification will be described with preliminary hypernuclear mass spectrum.