Neutrino08 - Sarkar

Subir Sarkar is one of those rare individuals who can be very critical of his audience without offending anybody (that I know of) because he just makes so much sense. He was assigned the task (by the organisers) of analysing the implications of cosmic ray results. The talk included phrases such as:

one could use some Mickey Mouse model of mirror [something] ...

or even better, to the audience:

please stop drawing limits ...

in reference to ideas which have been completely ruled out. The talk began with the catchphrase guaranteed cosmogenic neutrino flux, to which Sarkar had added strong quotation marks to the first word, the main point being that cosmic ray primaries might well be heavy nuclei rather than protons. Auger data was used as evidence for this hypothesis, which is consistent with the observed energy spectrum and predicts a smaller cosmogenic flux.

Another 2006 paper looks at Auger bounds for QCD. Colour gluon condensates were mentioned. The steep rise of gluon density at low x should saturate, leading to a supression of the neutrino-nucleus cross section. In summary, he says that neutrino observations are a unique laboratory for both Standard Model and Beyond Standard Model physics.