Examining possible neutron-halo nuclei heaver than ${}^{37}$Mg

Abstract

The even-Z odd-N neutron-halo nuclei, which are the possible lightest neutron-halo nuclei heavier than ${}^{37}$Mg, are explored by studying the shell-structure unique in weakly-bound neutrons for spherical or deformed shape. It is pointed out that due to the narrowed N=50 spherical energy-gap and a few resulting close-lying neutron one-particle levels, 1g${}_{9/2}$, 3s${}_{1/2}$, and 2d${}_{5/2}$, for spherical shape, nuclei with some weakly-bound neutrons filling in those levels may be deformed and have a good chance to show deformed s-wave halo. Promising candidates are ${}_{24}^{71}$Cr${}_{47}$, ${}_{24}^{73}$Cr${}_{49}$, ${}_{24}^{75}$Cr${}_{51}$ and ${}_{26}^{77}$Fe${}_{51}$ in the case that those nuclei lie inside the neutron drip-line. An interesting possibility of the deformed p-wave or s-wave halo is suggested also for the nucleus ${}_{18}^{53}$Ar${}_{35}$.

Comments: 13 pages, 2 figures