Search for light sterile neutrinos with two neutrino beams at MicroBooNE

The existence of three distinct neutrino flavours is a central tenet of the Standard Model of particle physics. During the past few decades, a number of anomalous observations inconsistent with the three-flavour picture have motivated a popular hypothesis that an additional neutrino state could exist, which does not interact directly with matter, therefore called a ’sterile neutrino’. MicroBooNE was built to test these anomalies, in particular those seen in the LSND and MiniBooNE experiments. In a recent paper published in Nature, we measure — for the first time — data from two different neutrino beams in a single detector, using the MicroBooNE liquid-argon time projection chamber. In this talk I will show that the use of two accelerator neutrino beams allows us to break a degeneracy between electron neutrino appearance and disappearance, which had previously weakened the sensitivity to the sterile neutrino hypothesis, and present the results of this search, which excludes the single sterile neutrino explanation of the LSND and MiniBooNE anomalies at 95% confidence level, as well as a notable portion of the parameter space that could explain the gallium anomaly.