Opening the energy window on direct dark matter detection

TL;DR

Expanding the energy analysis window in direct dark matter detection enhances the ability to constrain interaction models, improve parameter estimation, and test astrophysical properties of dark matter halos.

Contribution

This work demonstrates the benefits of extending the energy range in direct detection experiments, optimizing energy windows for better dark matter characterization and astrophysical tests.

Findings

Optimal energy windows are around 500 keV for xenon and 300 keV for argon.

Enlarged energy ROI improves dark matter mass and coupling measurements.

Opening the energy window helps distinguish interaction models and test halo parameters.

Abstract

In this article we investigate the benefits of increasing the maximum nuclear recoil energy analysed in dark matter (DM) direct detection experiments. We focus on elastic DM-nucleus interactions, and work within the framework of effective field theory (EFT) to describe the scattering cross section. In agreement with previous literature, we show that an increased maximum energy leads to more stringent upper bounds on the DM-nucleus cross section for the EFT operators, especially those with an explicit momentum dependence. In this article we extend the energy region of interest (ROI) to show that the optimal values of the maximum energy for xenon and argon are of the order of 500 keV and 300 keV, respectively. We then show how, if a signal compatible with DM is observed, an enlarged energy ROI leads to a better measurement of the DM mass and couplings. In particular, for a xenon detector, DM masses of the order of 200 GeV (2 TeV) or lower can be reconstructed for momentum-independent (-dependent) operators. We also investigate three-dimensional parameter reconstruction and apply it to the specific case of scalar DM and anapole DM. We find that opening the energy ROI is an excellent way to identify the linear combination of momentum-dependent and momentum-independent operators, and it is crucial to correctly distinguish these models. Finally, we show how an enlarged energy ROI also allows us to test astrophysical parameters of the DM halo, such as the DM escape speed.