Fission of heavy hypernuclei formed in antiproton annihilation

Heavy hypernuclei are produced in the annihilation of antiprotons in [sup 238]U. The delayed fission of heavy hypernuclei and hypernuclei of fission fragments are observed by using the recoil-distance method in combination with measurement of secondary electron multiplicity. The lifetime of hypernuclei in the region of uranium is found to be (1.25[plus minus]0.15)[times]10[sup [minus]10] sec. It is observed that [Lambda] hyperons predominantly stick to the heavier fission fragments. The yield of hypernuclei is found to be (7.4[plus minus]1.7)[times]10[sup [minus]3] per stopped antiproton. No coincidences with [ital K][sup +] were found. Statistical and systematic errors on the number of events expected do not rule out this possibility.