Parity-odd Neutrino Torque Detection
  Cosmological observations are promising ways to improve our understanding of
neutrino mass properties. The upper bound on the sum of masses is given by the
cosmic microwave background and large scale structure. These measurements are
all parity-even, and potentially contaminated by unmodeled baryonic effects. In
this paper we propose a novel parity-odd gravitational effect of neutrinos: A
unique contribution to the directions of the angular momentum field of galaxies
and halos. This observable is free of contamination in linear perturbation
theory, and thus likely more cleanly separated from other nongravitational
effects. A deep 21-cm survey to redshift 1 can potentially yield a $5\sigma$
significance on neutrino mass detection for a fiducial sum of neutrino masses
of 0.05 eV.
