Dr Patrick Green

Abstract:

We report results from an updated search for neutral current (NC) resonant $\mathrm{\Delta }(1232)$ baryon production and subsequent $\mathrm{\Delta }$ radiative decay (NC $\mathrm{\Delta }\to N\gamma$ ). We consider events with and without final state protons; events with a proton can be compared with the kinematics of a $\mathrm{\Delta }(1232)$ 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 $\mathrm{\Delta }\to N\gamma$ 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 $\mathrm{\Delta }\to N\gamma$ events with and without final state protons, our data exclude an interpretation in which all excess events have associated protons at $2.0\sigma$ , and are consistent with an interpretation in which all excess events have no associated protons at  $0.63\sigma$ .

Abstract:

We report the measurement of the triple-differential cross section d 3 σ / d E vis d cos ( θ μ ) d P μ for inclusive muon-neutrino charged-current scattering on argon. This measurement utilizes data from 6.4 × 10 20 protons on target of exposure collected using the MicroBooNE liquid argon time projection chamber located along the Fermilab Booster Neutrino Beam with a mean neutrino energy of approximately 0.8 GeV. The mapping from reconstructed kinematics to truth quantities is validated within uncertainties by comparing the distribution of reconstructed hadronic energy in data to that of the model prediction in different muon scattering angle bins after applying a conditional constraint from the muon momentum distribution in data. The success of this validation provides confidence that the energy transfer in the MicroBooNE detector is well-modeled within simulation uncertainties, enabling a reliable unfolding to a triple-differential cross section defined at the nominal neutrino flux over muon momentum, muon scattering angle, and visible neutrino energy. This validation not only supports accurate cross-section extraction, but also establishes a critical foundation for tuning interaction models used in future neutrino oscillation measurements. The unfolded measurement covers an extensive phase space, providing a wealth of information useful for future liquid argon time projection chamber experiments measuring neutrino oscillations. Comparisons against a number of commonly used model predictions are included and their performance in different parts of the available phase-space is discussed.