New results from the UCN$\tau$ experiment

A precise determination of the neutron lifetime $\tau_{n}$, when combined with other neutron $\beta$-decay observables, provides a stringent test of the standard model. The UCN$\tau$ experiment at the Los Alamos Neutron Science Center (LANSCE) uses a magneto-gravitational neutron trap to confine ultracold neutrons (UCN) without loss due to material interactions prevalent in previous UCN bottle experiments. The experiment uses a novel \textit{in situ} detector to count UCN at different locations within the trap. These features allowed us to perform the first measurement of $\tau_{n}$ with systematic corrections no larger than the associated uncertainties. Since reporting this measurement in 2018, we have acquired enough data to achieve $\sim 0.3$ s statistical uncertainty. Further, we implemented a UCN buffer volume between the LANSCE UCN source and the apparatus, allowing us to better normalize the number of neutrons loaded into the trap. I will discuss the improved UCN$\tau$ experiment and present new results from data acquired in 2017 and 2018.