Neutrino footprint in Large Scale Structure

TL;DR

This paper demonstrates that neutrinos leave a detectable large-scale structure footprint, which can confirm their mass scale through cosmological data, linking astrophysics and particle physics.

Contribution

It identifies a neutrino signature on large linear scales that is robust against systematics, aiding in confirming neutrino mass measurements from cosmology.

Findings

Neutrinos cause a measurable footprint on large, linear scales.

The feature's properties relate to neutrino mass splitting and power suppression.

Detection of this feature can confirm the absolute neutrino mass scale.

Abstract

Recent constrains on the sum of neutrino masses inferred by analyzing cosmological data, show that detecting a non-zero neutrino mass is within reach of forthcoming cosmological surveys, implying a direct determination of the absolute neutrino mass scale. The measurement relies on constraining the shape of the matter power spectrum below the neutrino free streaming scale: massive neutrinos erase power at these scales. Detection of a lack of small-scale power, however, could also be due to a host of other effects. It is therefore of paramount importance to validate neutrinos as the source of power suppression at small scales. We show that, independent on hierarchy, neutrinos always show a footprint on large, linear scales; the exact location and properties can be related to the measured power suppression (an astrophysical measurement) and atmospheric neutrinos mass splitting (a neutrino oscillation experiment measurement). This feature can not be easily mimicked by systematic uncertainties or modifications in the cosmological model. The measurement of such a feature, up to 1% relative change in the power spectrum, is a smoking gun for confirming the determination of the absolute neutrino mass scale from cosmological observations. It also demonstrates the synergy of astrophysics and particle physics experiments.