Excess radiation in the Universe - A possible probe of physics beyond the standard model

Steen Hannestadt (Aarhus)
DESY Auditorium, 17:00 h

The standard models of particle physics and cosmology provide a firm prediction for the amount of energy density in relativistic particles in the Universe. While most of this radiation is in the form of photons, the cosmic microwave background, an almost equal amount is hidden in the cosmic neutrino background. This background can be measured indirectly using precision cosmology and provides one of the main windows of cosmology to physics beyond the standard model. Intriguingly, there is tentative evidence that the energy density in neutrinos (or other weakly interacting, light particles) is higher than predicted by the standard model. In the talk I will review the current measurements and their implications, as well as discuss future measurements of the cosmic radiation density.

application/pdf Transparencies (5.3 MB)
Transparencies Hannestad