From my days as a graduate student, I have long been interested why the Universe exhibits a strong bias toward matter. The Big Bang would have produced equal amounts of matter and antimatter, but today we see only a smidgen of antimatter present, produced, for example, in Earth's upper atmosphere by collision of cosmic rays with air molecules or in esoteric processes in sundry physics laboratories. The stars, planets, people and cabernet sauvignon we see are all made from matter. Where did the antimatter go? (In technical terms, what is the source of "CP violation" in the early universe that leads to the observed preponderance of matter over antimatter?)

A possible path to understanding why any matter at all is present in our Universe (including the matter that comprises us) is to understand the behavior of neutrinos, especially mysterious subatomic particles. Almost a billion times more numerous in the Universe than hydrogen, the Universe's most abundant element, but with a mass more than a million times smaller than an electron's, the electrically neutral neutrino interacts extraordinarily feebly with matter. (A common reference scale is that a neutrino needs to travel a distance of a light year through lead before interacting.) Neutrinos also have the peculiar property that they morph from one type (or "flavor") to another as they travel.

The morphing of a muon flavor neutrino to an electron flavor neutrino is particularly interesting and has not yet been observed. (The flavor of a neutrino is determined by what electrically charged particles it produces when it eventually interacts with matter. An electron neutrino produces electrons while a muon neutrino produces a muon, a kind of heavy, radioactive electron.) The whole phenomenon of neutrino morphing ("neutrino flavor oscillation") is poorly understood but needs to be if neutrino interactions in the early Universe can be sensibly thought to be central to explaining the subsequent absence of antimatter (i.e., "baryogenesis through leptogenesis")

An experiment ( "NOνA" ) I collaborate on will produce large numbers of muon neutrinos in a particle beam at Fermi National Accelerator Laboratory near Chicago and send them 810 kilometers away to to a very large detector being built just south of thew US-Canada border. This "far" detector is massive (15 kilotons) to contain enough target nuclei for the neutrinos to interact with. The far distance between source and detector allows time for the muon neutrinos to morph into electron neutrinos. NOνA will detect the morphing of muon neutrinos into electron neutrinos by detecting the creation of electrons in the far detector. Measuring the frequency of this particular morphing is one important science goal of the NOνA experiment. Data taking will begin in 2013 and run for at least six years.

Understanding NOνA's detector response and its calibration will require substantial computer simulation and reduction of real data from prototype running that starts in Summer 2010. The SMU high performance computing cluster will play a substantial role in this effort.

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