Rejecting P and CP-invariance in scalar dark matter-nucleus interactions

Abstract

There is convincing evidence that a significant fraction of the mass in our Universe consists of non-baryonic and non-luminous dark matter. The particles forming this cosmological component have so far escaped detection, but are currently searched for at direct detection experiments. These search for non-relativistic dark matternucleus scattering events in low-background, deep underground detectors. In this thesis, the properties of spin-0 dark matter-nucleus interactions under P and CPtransformations are investigated, assuming that a dark matter signal has been observed at direct detection experiments. Using an effective theory to describe these interactions, the scattering events can be restricted to three cases: Conserving CP and P; Conserving CP, but violating P; and violating both CP and P. By performing a likelihood ratio test with simulated data, this thesis aims to determine how many observed scattering events are required in order to discriminate one case from the other in the next generation of direct detection experiments.