Enhanced search for neutral current Δ radiative single-photon production in MicroBooNE

We report results from an updated search for neutral current (NC) resonant Δ ( 1232 ) baryon production and subsequent Δ radiative decay (NC Δ → N γ ). We consider events with and without final state protons; events with a proton can be compared with the kinematics of a Δ ( 1232 ) baryon decay, while events without a visible proton represent a more generic phase space. In order to maximize sensitivity to each topology, we simultaneously make use of two different reconstruction paradigms, Pandora and Wire-Cell, which have complementary strengths, and select mostly orthogonal sets of events. Considering an overall scaling of the NC Δ → N γ rate as an explanation of the MiniBooNE anomaly, our data exclude this hypothesis at 94.4% CL. When we decouple the expected correlations between NC Δ → N γ events with and without final state protons, our data exclude an interpretation in which all excess events have associated protons at 2.0 σ , and are consistent with an interpretation in which all excess events have no associated protons at 0.63 σ .