Speaker
Description
We present the first experimental search for neutrino-induced neutral current (NC) coherent single-photon production using data from the MicroBooNE liquid argon time projection chamber (LArTPC). MicroBooNE is located on-axis in the Fermilab Booster Neutrino Beam (BNB) with an average neutrino energy of approximately 0.8 GeV. The 85-tonne active volume provides excellent electromagnetic shower reconstruction capabilities to search for this rare process. This search targets neutrino interactions with a single, photon-like electromagnetic shower and no visible vertex activity in the final state. This signature is characteristic of NC coherent single-photon production. Using three years of data from the BNB, we establish the world's first experimental limit on this process, placing an upper bound on the flux-averaged cross section of σ < 1.49 × 10⁻⁴¹ cm² at 90% C.L. We also present the status of a search for a heavy neutrino with large transition magnetic moments (TMM), which has a similar experimental signature. This search leverages the NC coherent single-photon analysis with improved low-energy vertex hadronic activity veto tools.