Fission of heavy hypernuclei formed in antiproton annihilation
Résumé
Heavy hypernuclei are produced in the annihilation of antiprotons in
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±0.15)×
10
−
10
sec. It is observed that Λ hyperons predominantly stick to the heavier fission fragments. The yield of hypernuclei is found to be (7.4±1.7)×
10
−
3
per stopped antiproton. No coincidences with
K
+
were found. Statistical and systematic errors on the number of events expected do not rule out this possibility.