The 288th RIKEN RIBF Nuclear Physics Seminar
Lecturer: Dr. Chen Sidong
(Department of Physics, The University of Hong Kong)
Title: Structural evolution of neutron-rich calcium isotopes
* The talk will be given in English
Date: May 26th (Tues.) 2020 15:00-
Place: via Zoom
(the URL was distributed in the mailing list and the number of audience is up to 100)
The calcium isotopes, which have 20 protons (Z=20), are one of the most
interesting isotopic chains to study nuclear structure. Due to the
closed proton shell, the structural evolution is governed by the
neutrons. Using the intense radioactive beams at RIBF, the first
experimental evidence of the N=34 sub-shell closure was found in 54Ca
. More recent in-beam gamma-ray spectroscopic studies aimed at a
detailed study on the nature of the N=34 sub-shell closure of 54Ca and
the nuclear structures in its vicinity.
More specifically, the N=34 sub-shell closure of 54Ca was investigated
by quasifree one-neutron knockout reactions. Using the in-beam γ-ray
technique tagging on the final states of 53Ca, the exclusive cross
sections and momentum distributions were measured. A significantly
larger cross section to the p3/2 state compared to the f5/2 state in
53Ca corroborated the arising of the N=34 sub-shell closure in calcium
isotopes . Furthermore, spectroscopic information for calcium
isotopes beyond the N=34 sub-shell closure was obtained for the first
time by measuring the de-excitation γ rays of 56,58Ca following
one-proton knockout reactions. The observations were confronted with
several state-of-the-art theoretical calculations, allowing for a
prediction of the structure of 60Ca.
In this seminar, the study on the N=34 sub-shell closure of 54Ca, as
well as the structural information on 56,58Ca will be discussed in detail.
 D. Steppenbeck et al., Nature, 502, 207-210, (2013).
 S. Chen et al., Phys. Rev. Lett. 123, 142501 (2019).