High spin states inPb208

Abstract

Proton cross sections forPb have been measured for elastic and inelastic scattering to the 12+, 6.10 MeV, 12&, 6.43 MeV, 122, 7.06 MeV, and 14, 6.74 MeV states at Ep =318 MeV. We analyze the inelastic transitions in the distorted wave impulse approximation and use the previously published electron scattering results to constrain the wave functions in the unnatural parity calculations. A 13 state is discussed as an unresolved "contaminant" to the 12~, 6.43 MeV state. Mixing between the 12 neutron and proton particle-hole configurations is found to reduce substantially the differences reported previously in observed proton and electron quenching factors. This results in greater quenching for the 12&, 7.06 MeV state, and less quenching for the 12&, 6.43 MeV state than was previously reported in (e, e') analyses.

?-decay of the particle-hole states with the highest spins in208Pb

“…Lichtenstadt [2] assigned an 11 § level at 5.27 MeV in inelastic electron scattering; this might be the same state, although the energy deviation for other levels in this region between his (e, e') study and the 2~ ey) data [14,16] is typically 10keV or better. A more recent (e, e') experiment by Connelly [5] has been found in (p,p') at 35 MeV [7], at 135 MeV a 12 + level at 6.076(23) MeV [9] and also with 318 MeV a state at 6.10 MeV [6]. Therefore it is clear that a 12 + level exists very close to 6.10 MeV, and because the reaction mechanism of the present experiment strongly favours yrast states, we assign the 865.4 keV line as the 12 + ~ 111 + transition.…”

“…The ydecay of the four lowest 10 + states has been seen [14] in c~-7 coincidences with the selective and favourable 2~176 reaction, that populates the 7~h9/2h~) 2 configuration. The highest spin states to 14-have been measured in (e,e') and (p,p') [3,4,6,8,9]. y-spectroscopy of these levels can bring the mostly separated fields together and the combination of experimental data that are sensitive to quite different aspects of nuclear structure together with a very good theoretical basis by the shell model for 2~ is particularly interesting.…”

“…Two particletwo hole states are typically 2 MeV higher and should not mix much. Highly elaborated experiments with inelastic electron [1][2][3][4][5] and proton [6][7][8][9][10][11] (including polarized protons) scattering and charged particle transfer [12] have been performed, in order to find these levels and determine their structure. Simultaneously, because the structure is relatively well known, the reactions on 2~ are used to understand the reaction mechanism and determine free parameters in the reaction theory as the effective charge and magnetic quenching in electron scattering.…”