=Date and Place=
July 6th (Tue) , 15:00~ via ZOOM meeting system
Dr. Leung Tsz Tang
(Argonne National Laboratory)
Study the role of the valence proton in 23,25F using the (p,2p) quasi-free knockout reaction
A large difference of the neutron dripline between oxygen and fluorine suggests that the 0d5/2 proton changed the neutron shell structure in fluorine. The quasi-free 23,25F(p,2p) direct knockout reactions in inverse kinematics was used to study the role of the proton. The valence proton in 23,25F should be a single-particle due to the Z=9 magicity and sub-closed neutron shell. When the proton is removed from the 23,25F, the neutron shell structure will project to oxygen excited states, and from that, the neutron shell structure can be inferred.
We will talk about the experimental setup, the data analysis, and the results. The occupation number of the 0d5/2 proton of 25F was 1.0 ± 0.3, which is consistent with a single-particle state. However, the spectroscopic strength of the 0d5/2 proton was fragmented, particularly, the ground-state strength is weak. This indicates that the neutron-shell structures between 23,25F and 22,24O are different. The experiment was condensed to Physical Review Letters 124, 212502 (2020).