Revisiting the Fermionic Dark Matter Absorption on Electron Target

TL;DR

This study systematically analyzes fermionic dark matter absorption on electron targets using effective field theory, revealing unique spectral signatures, constraining parameters with experimental data, and exploring cosmological and astrophysical implications.

Contribution

It provides a comprehensive EFT framework for fermionic DM absorption, identifies distinctive spectral features, and sets new bounds from current and future experiments.

Findings

Preferred DM masses at 59 keV and 105 keV from Xenon1T and PandaX-II data.

Probed cutoff scale up to around 1 TeV.

Established constraints on tensor and pseudo-scalar operators.

Abstract

We perform a systematic study of the fermionic DM absorption interactions on electron target in the context of effective field theory. The fermionic DM absorption is not just sensitive to sub-MeV DM with efficient energy release, but also gives a unique signature with clear peak in the electron recoil spectrum whose shape is largely determined by the atomic effects. Fitting with the Xenon1T and PandaX-II data prefers DM mass at $m_\chi = 59$keV and 105keV, respectively, while the cut-off scale is probed up to around 1TeV. The DM overproduction in the early Universe, the invisible decay effect on the cosmological evolution, and the astrophysical X(gamma)-ray from the DM visible decays are thoroughly explored to give up-to-date constraints. With stringent bounds on the tensor and pseudo-scalar operators, the other fermionic DM operators are of particular interest at tonne-scale direct detection experiments such as PandaX-4T, XENONnT, and LZ.