Speaker
Description
Dark matter interaction with the atomic electron is a
well-motivated problem in recent years. As the nature of DM and its
non-gravitational interactions with normal matter are still unknown, instead of
considering a specific, well-motivated method, we are using multi relativistic
random-phase approximation (MCRRPA) and Frozen core approximation (FCA) in
the present study. Recently, the relativistic random-phase approximation (RRPA)
has been applied, with remarkable successes, to photoexcitation and
photoionization of closed-shell atoms and ions of high nuclear charge, such as
heavy noble gas atoms, where the ground state is well isolated from the excited
states. 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 interaction 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. Also, the energy
transferred by the dark matter particle to the target depends on the reduced mass
of the system. Therefore, the current sensitivity of direct detection experiments is
limited to a few GeV masses of dark matter particles due to their high energy
thresholds for detecting nuclear recoils. The sub-GeV dark matter is a less
explored region and highly motivated for next-generation experiments. In this work,
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 method is used to evaluate the SD and SI atomic
ionization cross-sections of LDM-electron scattering. Our new atomic responses
function to be numerically important in a variety of cases and can mold it with any
dark matter velocity distribution, which we identify and investigate thoroughly using
effective theory methods. We then use our atomic responses function to calculate
differential cross sections within 5% error in RRPA and 20% in FCA. Detailed
results will be presented at the meeting. This work was supported by the Ministry
of Science and Technology (MOST) of Taiwan.
