MiniBooNE at GeneFest 2010

I spent Saturday shut in a windowless room, knowing that there was glorious weather outside - and I'm not complaining one bit. I was here at Penn, in a lecture theater in my department, attending GeneFest 2010 - celebrating my colleague Gene Beier's contributions to physics over his 40 year career here. Gene has been around long enough, and worked broadly enough that his interests and career can't be summarized in a couple of sentences. But for a significant period, he has been one of the leaders in the neutrino physics community, and hence much of the program was focused on that. I won't report on all the talks, although they were uniformly good, but it turns out that the first one provided a useful summary of something I am interested in but have lost track of in the last few months. The speaker was Richard Van de Water from Los Alamos, who is the co-spokesman for the MiniBooNE experiment at Fermilab, designed to test the neutrino oscillation results claimed by the LSND experiment, that have worried the community to one degree or another for over a decade. LSND (Liquid Scintillator Neutrino Detector) was based at Los Alamos and measured accelerator-produced neutrinos. The resulting observations, in conjunction with other measurements of solar neutrino oscillations, disagree with the standard model with its three flavors of neutrinos. Thus, if the LSND results are correct, some fascinating new physics has been discovered. MinibooNE first reported results in 2007, in a run where they were using neutrinos, as opposed to the antineutrinos that LSND used. If the CP and CPT symmetries hold for this experiment (as people usually assume), then the neutrino results should be directly relevant to the LSND result, with which they didn't agree. However, in the last few months (I discovered yesterday) MiniBooNE recently reported updated results on their antineutrino runs - a direct test of LSND. Fascinatingly, to me, they have found a different result from the neutrino one, with an oscillation probability resembling that found by LSND! (See the actual talk for a detailed description). I should mention that currently these results are not at high enough confidence levels to get too worked up about. However, if they hold up to higher confidence levels, and turn out to be correct, then something quite remarkable is going on here (so remarkable, in fact, that truly airtight evidence would be needed), and future experimental work and frantic theoretical scrambling will be required. This is definitely something to keep an eye on.