Massive relic neutrinos in the galactic halo and the knee in the cosmic ray spectrum

TL;DR

This paper proposes that the mysterious 'knee' in the cosmic ray spectrum around 10^15.5 eV may be caused by interactions between cosmic rays and massive neutrinos in the galactic halo, linking neutrino properties to cosmic ray features.

Contribution

It introduces a novel explanation for the cosmic ray 'knee' involving massive neutrinos and their magnetic dipole moments, connecting astrophysical observations with particle physics.

Findings

The 'knee' energy correlates with neutrino mass via simple kinematics.

Interaction cross section needed exceeds Standard Model predictions but fits with a small neutrino magnetic dipole moment.

Neutrino parameters derived are consistent with current laboratory bounds.

Abstract

Despite many efforts to find a reasonable explanation, the origin of the "knee" in the cosmic ray spectrum at energy around 10**15.5 eV remains mysterious. In this letter we suggest that the "knee" may be due to a GZK-like effect of cosmic rays interacting with massive neutrinos in the galactic halo. Simple kinematics connects the location of the "knee" with the mass of the neutrinos, and, while the required interaction cross section is larger than that predicted by the Standard Model, it can be accommodated by a small neutrino magnetic dipole moment. The values for the neutrino parameters obtained from the analysis of existing experimental data are compatible with present laboratory bounds.