## Thursday, September 30, 2010

### Neutrinos and the CMB

If one asks an astronomer in which direction the solar system moves with respect to the Milky Way, they will point towards the star Vega in the constellation Lyra. This is the direction that the DAMA experiment considered under the hypothesis of a dark matter aether in the galactic halo, with respect to which the Earth's motion either adds or subtracts to the solar system motion depending on the time of year.

But if one looks at the location of Vega in the sky, it is roughly correlated with the dipole anisotropy in the cosmic microwave background radiation. This was pointed out in 2008 by Richard Saam (and no doubt others) and it means that we could consider a CMB origin for the DAMA results. This is fortunate, because we were already wondering about the coincidence between the CMB temperature and the (lightest) antineutrino rest mass.

The error bars on the DAMA annular modulation phase are surely large enough to accomodate this alternative origin for their observation. As Saam notes, the maximum of the DAMA cosine corresponds to a minimum in the Earth's motion with respect to the CMB. This would be in agreement with larger cross sections with the wondrous neutrino sector around early June. Thus there is no need to posit a galactic aether.

#### 1 comment:

1. A little clarification:

1. It is important to note that the CMB is NOT just another kind of aether, although that is essentially the way it is commonly viewed. In this picture, it is very much observer dependent.

2. This is not in any way a proposal to extend the neutrino sector to so called sterile neutrinos. Graham D's main point is that the abundances are radically altered, but we also care about black holes and the like. And rather than Graham D's semi neutrino annihilation picture, I prefer ... let's call it a transmutation process for neutrinos and CMB photons.