Nuclear Physics Seminar with Nicolas Dronchi on Breakdown of the N=20 shell gap closure in 36/38Ca and early 7Li results
In a pair of experiments, the B(E2; 0+g.s -> 2+1) and proton branching ratio was measured for 36Ca. The values point to an increased proton fp shell occupancy in the ground state indicating the N=20 gap between the sd-pf shells has been broken. These data points also provide an update on the previous use of 36Ca/36S mirror pair in the determination of the slope of the symmetry energy with density L as well as help reduce uncertainties of an rp-process waiting point.
I will also discuss our early results in the search for a new excited state in 7Li which was predicted using the NCSMC [1]. They predict an S-wave resonance just above the particle decay threshold to 6He+p indicating a near threshold resonance. No clear evidence for this resonance was measured.
[1] Matteo Vorabbi, Petr Navrátil, Sofia Quaglioni, and Guillaume Hupin. Be-7 and Li-7 nuclei within the no-core shell model with continuum. Physical Review C, 100(2):024304, Aug 2019.