Ponente
Descripción
Islands of Inversion (IoI) are among the most intriguing phenomena in nuclear structure research. One of the least understood is the so-called $N=40$ IoI, centred around $^{64}$Cr ($Z=24$, $N=40$). Situated just below the spherical $^{68}$Ni ($Z=28$, $N=40$), the interplay between the negative-parity $pf$ neutron shell and the positive-parity $g_{9/2}$ and $d_{5/2}$ orbitals (spanning the well-established $N=50$ shell gap) induces a strong deformation [1].
Despite the growing interest in this region of the nuclear chart, very little is known about $^{64}$Cr due to its challenging production. Reaction-based studies have tentatively identified the yrast band up to the $6^+$ state, and a Coulex experiment measured the B(E2) of the first $2^+$ state, albeit with a large error bar [2]. An experiment at the NSCL studied the beta decay of $^{64}$V but observed only 3 or 4 counts of the $2^+ \rightarrow 0^+$ transition [3].
The combination of a high-efficiency HPGe array with RIBF’s ability to produce highly exotic isotopes presents a unique opportunity for the first comprehensive spectroscopy of $^{64}$Cr. One of the main goals of the experiment is to identify the proposed excited $0^+$ state, which would provide crucial evidence for shape coexistence in this region. Furthermore, this experiment would significantly complement the already approved NP1812-RIBF232, which aims to perform lifetime measurements in nearby nuclei.
[1] S. M. Lenzi, et al. Phys. Rev. C, 82:054301, 2010
[2] H. L. Crawford, et al. Phys. Rev. Lett., 110:242701, 2013
[3] S. Suchyta, et al. Phys. Rev. C, 89:067303, 2014
