Recently, revolutionary discoveries have shown that while the Standard Model represents a good approximation of nature at the energies of existing accelerators, it is incomplete. A striking development in neutrino physics, thanks to a remarkably broad suite of experiments, is the discovery that the three kinds, or "flavors," of neutrinos, previously thought to be massless, have mass and can oscillate (morph from one kind to another), contrary to the Standard Model.
These properties imply that neutrinos play critical roles across many fields of physics and make neutrinos uniquely suitable as probes for discovering new physics processes. Neutrinos have shown us details of the solar core, provided clues to the mechanism of supernova explosions, and most likely play an important role in the early universe. They may even be responsible for the observed preponderance of matter over antimatter.
By exploring physics beyond the Standard Model, LBNE will address fundamental questions about the universe:
Physicists have learned much over the past decade about building and operating large neutrino detectors and intense neutrino beams. The unique capabilities and accelerator infrastructure at Fermilab together with a potential far detector site 1,300 km away (a distance optimal for oscillation studies at the planned energies) at the Sanford Underground Research Facility in Lead, SD, present an extraordinary opportunity to develop a world-leading program of long-baseline neutrino science. LBNE aims to develop this research complex to measure the parameters that characterize three-flavor neutrino oscillations, study a phenomenon known as CP-violation, which may help explain the matter-antimatter imbalance, and determine the relative neutrino masses.
LBNE's capabilities will extend beyond long-baseline measurements. The experiment's observation of thousands of neutrinos from a core-collapse supernova in the Milky Way would allow us to peer inside a newly-formed neutron star, and potentially witness the birth of a black hole. Predicted rates for nucleon decay based on Grand Unified Theories cover a range directly accessible with the next generation of large underground detectors. LBNE's sensitivity to key decay channels, in particular, will offer unique opportunities for observation of this phenomenon.