Direct Measurement of Lifetime of Heavy Hypernucleus by JLab E02-017

JLab E02-017 aims to measure hypernucleus $^{208}_\Lambda$Pb lifetime with less than 5\% precision, much better than previous measurements in this mass range. The experiment will be carried out in August, 2005. The hypernucleus is produced by (e,e'K$^+$) reaction. The experiment utilizes the fine time structure of CEBAF electron beam. Hypernuclear delayed fission products are detected by a LPMWPC in coincidence with scattered K$^+$ to positively identify hypernuclear production and its weak decay. These techniques result in much improved time resolution and reduced background. The experimental setup will be described and the preliminary fission time spectrum will be presented.