Measurement of the Mean Life of the 4.49-MeV (5−) State ofCa40. Effects of Deformed Components on the Lifetimes of the Odd-Parity States

We have measured a mean life of 392 ± 12 psec for the 4.49-MeV ($5^{-}$) state of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, corresponding to an $E2\mathrm{}$ transition strength of 1.04 ± 0.03 Weisskopf units which is considerably stronger than that predicted by a one-particle, one-hole description of the states. However, this $E2\mathrm{}$ decay rate and those of eight other $E2\mathrm{}$ transitions between odd-parity states can be understood when the states are described as admixtures of deformed and spherical wave functions.