Spectroscopy of $^{86,87,88}$Se levels populated through beta decay of $^{86,87,88}$As

The overabundances of Sr, Y and Zr elements observed in some r-process-enriched, metal-poor stars complicate the quest for the r-process site. Jones et al$. $[Phys. Rev. C73, (2006)] reported an anomalously high 886-keV E(2$+)$ in $^{88}$Se$_{54}$ , which may be related to a doubly-magic $^{90}$Se$_{56}$. This new waiting point might explain the Sr, Y, Zr overabundances. A new experiment was carried out at NSCL to measure the structure of neutron-rich Se isotopes. New spectroscopic information of $^{86,87,88}$Se has been obtained through the beta decay of $^{86,87,88}$As nuclei. A gamma ray at 93 keV has been observed in the decay of $^{87}$As that could arise from the transition 5/2$^{+}$ to 3/2$^{+}$, as observed in the higher-Z N $=$ 53 isotones. A gamma-ray transition at 651 keV has been observed in the decay of $^{88}$As that could be a part of the yrast cascade in $^{88}$Se. The 886 keV gamma-ray observed by Jones et al. could not be verified.