Symmetry factor

So, what’s going to happen on April 11? Well according to rumors and some better-supported information, one of the Fermilab’s neutrino experiments, the MiniBooNE, will (finally, after a year of promises…) announce their results on nu_mu to nu_e oscillations.

What’s the big deal? Well, accroding to the Standard Model, there are only three types of neutrinos. Several neutrino oscillations experiments measured differences of masses of neutrino mass eigenstates squared (let’s call them Delta m^2_ij). A simple sum rule than says that if I take all measured Delta m^2_ij and sum them up, I’d get zero. Purely mathematically. Now, if I actually do that (i.e. with actual experimental results), I get a number that is far from zero. And the problem is a result from an old experiment called LSND.

Now I have two options. The boring one says that LSND result is wrong. It happens (not only to theorists…). The exciting one says that there are not three, but four (!) types of neutrinos. But the forth one is weird, it does not interact with anything, i.e. it is sterile. So MiniBooNE results will check LSND with either exciting or boring conclusion…

In other words, according to Maury Goodman:

*** MiniBooNE and boxing
Results of a short-baseline neutrino oscillation search from the MiniBooNE experiment at Fermilab are scheduled to be discussed at a seminar at Fermilab on April 11. MiniBooNE is sensitive to numu to nue oscillations at the same value of L/E as a reported signal from the LSND experiment at Los Alamos. I expect them to show the presence or absence of an excess of low energy electrons (below 2 GeV). The “blind” analysis has been done with a large amount of neutrino running. MiniBooNE is currently running with anti-neutrinos, and they got to do systematic checks with two unexpected antineutrino beam configurations for a few months. Ten metal plate were designed to provide an opportunity to shorten the length of the decay pipe and two of them fell down, inadvertently partially blocking part of that pipe. Repairs will be done 4/11.

Well explained. The rumor part of it is that they (MiniBooNE) see “something interesting.” One just have to check if they ordered champagne… although it might not be quite appropriate in light of recent unfortunate events at CERN…

Update (4/11/07): Standard Model withstood another test… no champagne, no trips to Sweden…