## Saturday, April 01, 2006

### Bush lost a few neutrinos in Minnesota

Foxnews informs that the federal government has lost a certain number of neutrinos between Illinois and Minnesota - but the loss is compensated by the information that the physicists gained. Neutrinos from the Fermilab travel throughout 450 miles of solid Earth to detectors in the Soudan Underground Mine State Park, MN that are burrowed hundreds of meters beneath the ground. This location has the advantage that the conventional cosmic rays are screened.

While Foxnews does not seem to tell us how many neutrinos were lost by the neutrino oscillations which makes their article rather useless for the physicists, they correctly argue that John Updike should update his poem to give neutrinos the weight they deserve. The wrong poem from 1960 is as follows:

Neutrinos: they are very small
They have no charge;
they have no mass;
they do not interact at all.
The Earth is just a silly ball
to them, through which they simply pass
like dustmaids down a drafty hall
or photons through a sheet of glass ...

The Britons tell you something more: 92 instead of 177 muon neutrinos were detected - about 50 percent - and I guess that the counting agrees with the mass matrix extracted from the previous oscillation experiments. According to the press release, the measured "delta(m2)" is "0.0031(06)(01) eV2". Here, (06) is the statistical uncertainty and (01) is the systematic uncertainty. The mixing angle satisfies

However, the error is still pretty large, of order 0.12. ;-) See also this graph.

More news articles about the MINOS experiment can be found here. A derivation of the neutrino oscillations may be found on page 13 or so of a student project of mine from the 1990s. Note that I considered the neutrino oscillations to be a fact long before they were "officially" discovered.

Update: In 2009, MINOS is going to find some very powerful evidence supporting cosmoclimatology, e.g. the correlation between the cosmic rays and the climate.