Parity-odd Neutrino Torque Detection

TL;DR

This paper proposes a novel parity-odd gravitational effect caused by neutrinos, which could enable a cleaner detection of neutrino mass through galaxy angular momentum orientations in future surveys.

Contribution

It introduces a new parity-odd observable related to neutrinos that is free from linear contamination, offering a potentially more accurate method for neutrino mass measurement.

Findings

Potential 5σ neutrino mass detection with deep 21-cm surveys

Observable is free from linear perturbation contamination

Offers a new approach to neutrino mass constraints

Abstract

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.