Constraints on spin independent dark matter scattering on electrons: Ge & Xe Detectors

Mukesh Kumar Pandey^1*, Chih-Pan Wu¹, Lakhwinder Singh³, Chung-Chun Hsieh¹, Jiunn-Wei Chen¹, Hsin-Chang Chi², C. P. Liu², Henry T. Wong³

¹Department of Physics, National Taiwan University, Taipei, Taiwan
²Department of Physics, National Dong Hwa University, Shoufeng, Hualien, Taiwan
³Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Mukesh Kumar Pandey, email:mkpandey@gmail.com

A generic class of cold dark matter is Weakly Interacting Massive Particles (WIMP), which receives the most attention among all dark matter candidates due to providing an elegant solution for the SM hierarchy problem and the “WIMP-miracle," that leads to a relic abundance comparable to the measured dark matter density with weak-scale couplings. In recent years, there has been remarkable progress made by direct dark matter detection experiments through novel innovations in detector technologies and the increase of detector sizes which are mostly motivated by the WIMP paradigm. In a specific DM scattering process, what are the contributions from the electronic and nuclear degrees of freedom? Even though the current common practice in constraining DM interactions is one type at a time, it is necessary to keep in mind that events measured by a detector are a sum from all possible sources. Furthermore, it is desirable from the experimental point of view to determine which process and kinematic region would be best to constrain a certain type of DM interactions with electrons or nucleons. For this purpose, one has to rely on theoretical analysis. In this work, we try to address the above questions using the atom, Germanium and Xenon—where most calculations can be carried out using nonrelativistic effective field theory. Calculation—and study its scattering with nonrelativistic LDM particles of a MeV to GeV mass range. The sub-GeV dark matter is less explored region and highly-motivated for next-generation experiments.
In this paper we are going to present the scattering of light dark matter (LDM) particles with atomic electrons in the context of nonrelativistic effective field theory. We consider both contact and long-range interaction between dark matter and atomic electron. A state-of-the-art many-body methods is used to evaluate the spin independent atomic ionization cross sections of LDM-electron scattering. We will present the new upper limits on parameter space spanned by dark matter effective coupling strength and mass using the superCDMSlite, low energy XENON10 and XENON100 ionization-only data.
This work was supported by the Ministry of Science and Technology (MOST) of Taiwan.

Keywords: WIMP, dark matter, atomic Detectors, New Constraints, Medium and High energy