The Why, What and Where of the Long Baseline Neutrino Experiment

Mary Bishai


Although the Standard Model of particle physics presents a remarkably accurate description of the elementary particles and their interactions, it is known that the current model is incomplete and that a more fundamental underlying theory must exist. Results from the last decade, that the three known types of neutrinos have nonzero mass implies physics beyond the Standard Model. It is now known that the 3 known neutrino flavor states are mixtures of different mass states. Thus the neutrinos mix with one another and oscillate between generations. While the magnitude of the mass differences of the 3 mass states are known, the ordering is not. The magnitudes of the 3 mixing angles that determine the mix of mass states in each flavor state are now known and are very different than the mixing in the quark sector. The 3x3 mixing of neutrinos implies the existence of a CP violating phase that is yet unknown. A non-zero CP phase would imply that CP is violated in the lepton sector which could shed light on the observed matter/anti-matter asymmetry in the Universe. I will describe how observations of (anti)muon-neutrino to (anti)electron-neutrino oscillations over a distance > 1000km are the key to unambiguously determining the neutrino mass ordering and detecting direct CP violation in the neutrino sector. The proposed Long Baseline Neutrino Experiment (LBNE) utilizes a high powered beam of (anti)muon neutrinos from Fermi National Laboratory directed at a massive neutrino detector located in the Homestake Mine 1300km from Fermilab. I will describe how the LBNE design choices and chosen technologies are optimized to maximize the sensitivity to CP violation, the neutrino mass ordering and to potential new physics beyond the 3-flavor neutrino model.