occasional meanderings in physics' brave new world

Name:
Location: New Zealand

Marni D. Sheppeard

## Saturday, May 31, 2008

### Neutrino08 Day 5e

M. Nakahata introduced supernova detection with 1987A and a long list of past and current detectors including Borexino, KamLAND, SuperK and LVD. He estimated about a 7% probability that a supernova at < 3.16 kpc will generate a 10% improvement in statistics. A detector with a reach of 20 kpc would cover 97% of galactic supernova potential. For SuperK, one expects around 100 16Oxygen CC events for a supernova at 10 kpc, and a total of 7300 ${\overline{\nu}}_{e} + p$ events. This should be capable of distinguishing between some models. The original neutrino temperatures would be discerned to around 10%. See here for a flux limit on relic neutrinos. To achieve high background reduction one requires neutron tagging in the water detector, and SuperK is introducing Gd for this purpose.

Astrophysical candidate sources were discussed by N. Bell. Deviations from the 1:1:1 ratio at Earth could arise for a number of exotic reasons. For example, a normal hierarchy $\nu$ decay could lead to a 5:1:1 (overabundant in electron neutrinos) observation.