Abstract: Neutrino oscillations, the spontaneous change from one neutrino "flavor" to another, is a major focus of the experimental particle physics community in both the US and abroad. The phenomenon of neutrino oscillation is well established, yet decades after its discovery we are just now on the brink of measuring the final parameters governing oscillation physics. One of the primary challenges for these experiments is the understanding of how neutrinos interact with detector material. We can constrain the critical inputs for interpreting neutrino experiments by combining experimental measurements with theoretical predictions. These nucleon amplitudes are the key ingredients needed for building nuclear models with realistic uncertainties in order to maximize physics discovery potential of neutrino oscillation experiments. In this talk, I will discuss neutrino-nucleon quasielastic scattering (QES), one of the primary signal measurement processes for neutrino oscillation experiments. The precision of QES is dominated by the nucleon axial form factor which must be understood from elementary target data. Recent experimental results and first principles supercomputer simulations with a technique called Lattice QCD have now drastically improved our understanding of neutrino interactions with free nuclei. These results show that the QES cross section has historically been underestimated by as much as 30%, well outside of the quoted uncertainties. Such a drastic change will have a significant impact upon next-generation neutrino oscillation experiments.
