Coherent neutrino scattering and the Migdal effect on the quenching factor

TL;DR

This paper investigates how the Migdal effect influences the germanium quenching factor at low energies, highlighting its potential to mimic signals in neutrino and dark matter experiments, and emphasizes the need for precise measurements.

Contribution

It demonstrates that the Migdal effect can significantly alter the quenching factor and affect interpretations of neutrino and dark matter signals, urging more precise low-energy measurements.

Findings

Migdal effect can mimic signals of light mediators in neutrino experiments.

Deviations from Lindhard model at low energies may be due to the Migdal effect.

Precise low-energy quenching factor measurements are crucial for accurate experimental interpretations.

Abstract

Recent measurements of the germanium quenching factor deviate significantly from the predictions of the standard Lindhard model for nuclear recoil energies below a keV. This departure may be explained by the Migdal effect in neutron scattering on germanium. We show that the Migdal effect on the quenching factor can mimic the signal of a light Z' or light scalar mediator in coherent elastic neutrino nucleus scattering experiments with reactor antineutrinos. It is imperative that the quenching factor of nuclei with low recoil energy thresholds be precisely measured close to threshold to avoid such confusion. This will also help in experimental searches of light dark matter.