title: Predominant time scales in fission processes in reactions of S, Ti and Ni with W: zeptosecond versus attosecond.
abstract: The inhibition of fusion by quasifission is crucial in limiting the formation of superheavy elements in collisions of heavy nuclei. Time scales of ∼10(-18)  s inferred for fissionlike events from recent crystal blocking measurements were interpreted to show either that quasifission itself is slower than previously believed, or that the fraction of slow fusion-fission is higher than expected. New measurements of mass-angle distributions for (48)Ti and (64)Ni bombarding W targets show that in these reactions quasifission is the dominant process, typically occurring before the system formed after contact has made a single rotation, corresponding to time scales of ≤10(-20)  s.
authors.affiliation: Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia.
authors.forename: R
authors.initials: R
authors.lastname: du Rietz
authors.forename: D J
authors.initials: DJ
authors.lastname: Hinde
authors.forename: M
authors.initials: M
authors.lastname: Dasgupta
authors.forename: R G
authors.initials: RG
authors.lastname: Thomas
authors.forename: L R
authors.initials: LR
authors.lastname: Gasques
authors.forename: M
authors.initials: M
authors.lastname: Evers
authors.forename: N
authors.initials: N
authors.lastname: Lobanov
authors.forename: A
authors.initials: A
authors.lastname: Wakhle