occasional meanderings in physics' brave new world

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Location: New Zealand

Marni D. Sheppeard

Saturday, May 31, 2008

Neutrino08 Day 5f

By mid afternoon the guy next to me, in the front row near the stage right under the bright lights, has fallen asleep. I guess not everybody here finds the theory talks interesting. Anyway, Richard Easther, an ex local, was next up with a talk on neutrinos and Future Concordance. He described the 6 basic input parameters, in particular $\Omega_{\Lambda}$, his description of which invoked a Tooth Fairy, which he pointed out might actually be a real tooth fairy under anthropomorphic thinking. The question is, how will the parameter set develop? It could shrink from knowledge of masses, or perhaps expand.

The important point is that the WMAP observations are now sufficiently accurate that neutrino physics is becoming essential to progress in cosmology. Limits indicate that $\sum m_{i}$ is probably less than 1 eV (yes, 0.06 eV) and Planck may well see to around 0.15. The second half of the talk was an intriguing analysis of the idea of a 21cm high $z$ map of the sky. This would require new foreground removal techniques and a very quiet radio location (perhaps the SKA in Western Australia)! See also this paper.

Let me briefly sketch the rest of Friday theory. Another theorist, Shaposhnikov, discussed his sterile neutrino scenario and methods for detecting them. Nir described the Sakharov conditions. In particular, the MSSM should be testable at the LHC, because parameter constraints indicate a $m_{\chi} < 250$ GeV (that's some funny stringy particle). Here is his introduction to Leptogenesis.