Octupole transitions in the²⁰⁸Pb region

Toward lifetime andgfactor measurements of short-lived states in the vicinity of208Pb

“…In this spectrum, the transitions from the low-spin states decaying to the ground state are clearly identified. The transition with an energy of 2485keV is the decay of the -19 2 excited state of 207 Pb built on top of the + 13 2 isomer [13,14]. This isomer at 1633keV is suggested to be built on the neutron-hole ni 13 2 .…”

“…This isomer at 1633keV is suggested to be built on the neutron-hole ni 13 2 . The state at 4119keV decays to this isomer by a 2485keV γray transition and has an octupole character [14]. The lifetime measurement of this state would allow us to determine whether it is a two-phonon vibration-coupled state [10] or not.…”

Structure of $^{207}$Pb Populated in $^{208}$Pb + $^{208}$Pb Deep-inelastic Collisions

“…Subsequent angular distributions were fitted with the function of the standard form W (θ) = A 0 {1 + A 2 P 2 (cos θ)}, where θ is the angle of the γ ray relative to the beam, A i are the angular distribution coefficients, and P i are the Legendre polynomials. From measurements of intense transitions in 208 Pb with known multipolarities, we expect stretched transitions to have: A 2 ∼ 0.36 for an octupole, A 2 ∼ 0.22 for a quadrupole, and A 2 < 0 for a dipole [4]. Angular distributions are shown in Fig.…”

“…Two shell model calculations were performed using the KHH7B and KHM3Y interactions, descriptions of which can be found in [4]. The KHH7B calculation used in this work differs from the prescription in [4], in that t = 1 proton and neutron mixing is considered. Figure 3 compares the calculations to the experiment, displaying a good agreement.…”

“…The differences between the calculations become apparent when looking to the octupole state, 19/2 − . Variations in the octupole state can be explained by the number of ∆j = ∆l = 3 pairs in each calculation, as discussed in [4]. …”