STATUS OF THE US LONG BASELINE NEUTRINO EXPERIMENT STUDY

The US Long Baseline Neutrino Experiment Study was commissioned jointly by Brookhaven National Laboratory and Fermi National Accelerator Laboratory to investigate the potential for future U.S. based long baseline neutrino oscillation experiments beyond the currently planned program. The Study focused on MW class convention at neutrino beams that can be produced at Fermilab or BNL. The experimental baselines are based on two possible detector locations: (1) off-axis to the existing Fermilab NuMI beamline at baselines of 700 to 810 km and (2) NSF's proposed future Deep Underground Science and Engineering Laboratory (DUSEL) at baselines greater than 1000 km. Two detector technologies are considered: a megaton class Water Cherenkov detector deployed deep underground at a DUSEL site, or a 100kT Liquid Argon Time-Projection Chamber (TPC) deployed on the surface at any of the proposed sites. The physics sensitivities of the proposed experiments are summarized. We find that conventional horn focused wide-band neutrino beam options from Fermilab or BNL aimed at a massive detector with a baseline of > 1000 km have the best sensitivity to CP violation and the neutrino mass hierarchy for values of the mixing angle θ13 down to 2.2o.