Probing P- and CP-violation in dark matter interactions

TL;DR

This paper demonstrates that future direct detection experiments can test for P- and CP-violation in dark matter interactions in a model-independent way, potentially revealing fundamental symmetry violations in DM-nucleus interactions.

Contribution

It introduces a model-independent framework to detect P- and CP-violation in dark matter interactions using direct detection data.

Findings

Between 10 and 300 signal events needed to reject P and CP invariance for 30 GeV DM.

Future experiments can potentially detect P- and CP-violation in DM interactions.

Analysis performed within a general effective theory for non-relativistic spin-0 DM-nucleus interactions.

Abstract

Discrete symmetries played a central role in elucidating the structure of the weak interactions, and they will probably be equally crucial regarding the interactions of the dark matter (DM) particle -- whose nature remains elusive. In this work we show that signals in future direct detection experiments can be used to test, in a model-independent way, for P- and CP-violation in DM-nucleus interactions. The analysis is performed within the most general effective theory for non-relativistic spin-0 DM-nucleus interactions mediated by the exchange of a heavy particle. Assuming an idealised xenon detector, we calculate the expected number of DM signal events required to reject P and CP invariant DM-nucleus interactions. For a DM mass of 30 GeV (or higher), this number lies between about 10 and 300 DM signal events, depending on how P and CP invariance are modeled. Future direct detection experiments, therefore, have the potential to reveal P- and CP-violation in DM interactions, making a decisive step toward the identification of the DM particle.