Update on the Neutron Decays to Dark Matter via the n→X+γ Branch

There is a 4 σ discrepancy between the free neutron lifetime measured via the "beam" method, which probes the p+e+$ar{ν}$ branch, and the "bottle" method, which probes the total decay rate. Theory by Fornal and Grinstein attempted to resolve such discrepancy by hypothesizing a Dark Matter + γ-ray decay branch for a free neutron, where an additional 1% decay branch could explain the discrepancy between two methods. At the Los Alamos UCN Source, during the 2018 beam cycle, a High-Purity Germanium (HPGe) detector was installed next to an ultracold neutron (UCN) buffer volume in the UCNτ beamline to search for a monoenergetic gamma peak associated with the Dark Matter decay mode. The statistical significance of this measurement is influenced by the knowledge of the number of UCN in the buffer volume, since this sets the upper bound on the expected intensity of the monoenergetic gamma peak. In addition to the previously measured UCN density, we have developed a detailed model of UCN transport to place additional constraints on the UCN density distribution in the buffer volume. In this talk, we will present the result of this search incorporating these new simulations to improve on previous null results that have been published and presented.