Letter of Intent FLARE Fermilab Liquid ARgon Experiments

Neutrinos have been a source of excitement lately. While the neutrino mixing has been expected, its pattern has taken us by surprise. The first evidence of physics beyond the standard model is here and more excitement is likely on the way.. Fermilab has a unique opportunity to take a lead in the neutrino physics in the next decade or so. Our recent major investments put us in an envi-able position of having two intense neutrino beams with energies spanning the range from 0.5 GeV to 20 GeV. To exploit fully our investment we need new experiment(s) matching the physics potential of our neutrino beams. Some of the most compelling questions can be addressed with a Fermilab, long baseline, off-axis experiment. A fortunate combination of the NuMI off-axis beam spectrum and the emerging value of ∆m 2 32 makes the distances offered by the NuMI beam nearly optimal for the ν e appearance experiment, which is the key to the most interesting questions: • what is the pattern of neutrino masses? " normal " or " inverted " hierarchy? • what is the value of the mixing angle sin 2 2θ 13 ? • is CP violated in the neutrino sector? We are very fortunate that a new powerful detector technology has been developed recently. This technology, the Liquid Argon Time Projection Chamber, is just waiting to be exploited. The Liquid Argon Time Projection Chamber is a relatively inexpensive detector ideally matched to the need of neutrino experiments. It provides a bubble-chamber like view of interactions thus enabling very efficient detection and classification of neutrino interactions. The long R&D effort of the ICARUS collaboration culminated in the successful operation of a 300 ton detector. Using the technology demonstrated by the ICARUS group one can construct a wide variety of neutrino experiments. The physics potential of neutrino beams is limited by the statistics of the available event sample which is proportional to a product of the beam intensity, the detector mass and the detection efficiency. While it is important to maximize the beam intensity it is equally important to take full advantage of the available beam by maximizing the detector mass and the detection efficiency. The high detection efficiency of a liquid argon detector makes its physics potential equivalent to that of a conventional detector with the beam power upgraded by the proton driver. 5 New, intense neutrino beams and advanced detection …