Measurement of Neutrino Masses from Relative Velocities

Understand

We present a new technique to measure neutrino masses using their flow field relative to dark matter.

• Present day streaming motions of neutrinos relative to dark matter and baryons are several hundred km/s, comparable with their thermal velocity dispersion.
• This results in a unique dipole anisotropic distortion of the matter-neutrino cross power spectrum, which is observable through the dipole distortion in the cross correlation of different galaxy populations.
• Such a dipole vanishes if not for this relative velocity and so it is a clean signature for neutrino mass.