Abstract
We present the mass excesses of , obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The mass of is determined for the first time, with an atomic mass excess of MeV. We find a significantly different two-neutron separation energy trend for neutron-rich isotopes of chromium, removing the previously observed enhancement in binding at . Additionally, we extend the trend for chromium to , revealing behavior consistent with the previously identified island of inversion in this region. We compare our results to state-of-the-art shell-model calculations performed with a modified Lenzi-Nowacki-Poves-Sieja interaction in the shell, including the and orbits for the neutron valence space. We employ our result for the mass of in accreted neutron star crust network calculations and find a reduction in the strength and depth of electron-capture heating from the isobaric chain, resulting in a cooler than expected accreted neutron star crust. This reduced heating is found to be due to the -MeV reduction in binding for with respect to values from commonly used global mass models.
8 More- Received 24 January 2016
DOI:https://doi.org/10.1103/PhysRevC.93.035805
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