What Atomic Physics Can Contribute to Direct Searches for Neutrinos and Light Dark Matters
Jiunn-Wei Chen1,2,3, Hsin-Chang Chi4, Cheng-Pang Liu4, Henry T. Wong5, Chih-Pan Wu1*
1Department of Physics, National Taiwan University, Taipei City, Taiwan
2Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei City, Taiwan
3Center for Theoretical Physics, Massachusetts Institute of Technology, Massachusetts, USA
4Department of Physics, National Dong Hwa University, Hualien, Taiwan
5Institute of Physics, Academia Sinica, Nankang, Taiwan
* presenting author:Chih-Pan Wu, email:d01222003@ntu.edu.tw
Dark matters and neutrinos are portals to new physics, and their properties can be studied by direct detection. Light Dark Matter (LDM) is an interesting and well motivated alternative to WIMP as a dark matter candidate. Because the energy exchange becomes lower, the direct searches for LDM have to rely on atomic responses such as (1) elastic scattering, (2) discrete excitation and (3) ionization from both nuclear and electronic recoils. We have applied an ab initio method, MCRRPA, to Ge and Xe atomic ionization by neutrinos within 5-10% accuracy, which is important to constrain new physics in the neutrino sector and to control the solar neutrino background for those ton-scale liquid xenon experimental collaborations. In DM ionization, we have analytically solved the hydrogen case, which serves an important case study for our future atomic many-body calculations using realistic targets, and some result with Ge target will be also presented.

Keywords: neutrino, light dark matter, direct detection, atomic effects