Measuring the neutrino-oxygen neutral-current quasielastic cross section using the Accelerator Neutrino Neutron Interaction Experiment

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is a 26-ton gadolinium-doped water Cherenkov detector located on-axis to Fermilab's Booster Neutrino Beam (BNB). ANNIE's primary physics goals include cross section measurements of neutrino-nucleus interactions in water, measuring final-state neutron multiplicity, and the deployment of novel detector technologies such as Large Area Picosecond Photodetectors (LAPPDs) and a water-based liquid scintillator (WbLS). ANNIE benefits from a short (100-meter) baseline, resulting in a large neutrino flux that enables high-statistics measurements. The experiment aims to measure the cross section for neutral current quasielastic (NCQE) interactions as part of its overall cross section measurements. Understanding the NCQE cross section is critical for reducing uncertainties in atmospheric neutrino backgrounds, especially in rare signal searches like the Diffuse Supernova Neutrino Background (DSNB). This measurement will also improve background constraints for long-baseline neutrino oscillation and proton decay experiments, enhancing overall sensitivity to new physics.