occasional meanderings in physics' brave new world

Name:
Location: New Zealand

Marni D. Sheppeard

## Monday, May 26, 2008

### Neutrino08 Day 1b

The afternoon's talks began with a report on the KamLAND antineutrino scintillator detector by Decowski. The antineutrinos come from 55 reactor cores throughout Japan, giving KamLAND an effective baseline of 180km. Current best values for the standard parameters, including solar neutrino results, are

$\Delta m^2 = 7.59 \times 10^{-5} (eV)^{2}$
$\textrm{tan}^{2} \theta = 0.47$

There is now a 6.2 terawatt upper limit on the (popular new crackpot idea of a) Earth's core georeactor. This was also discussed by McDonough, a real geochemist. He presented a beautiful introduction to the history of collaboration between physicists and geologists, from Lord Kelvin and Wiechert to the new potential of neutrino physics for geochemistry. One of the big questions in this field is the K/U ratio for Earth. Geoneutrinos result from U, K and Th $\beta$ decay chains. They form a small flux on top of the reactor background. To understand the mantle, this would best be investigated far from crustal regions, say near Hawaii deep under the ocean. Hanohano is an exciting proposal for a mobile detector, whose size is limited only by the requirement that the transporting barge fit through the Panama canal.