Impact of the Cherenkov Telescope Array (CTA) altitude on Dark Matter searches in the Milky Way Halo

TL;DR

This paper investigates how the altitude of the Cherenkov Telescope Array affects its ability to detect dark matter annihilation signals in the Milky Way halo, using simulations to compare different site altitudes.

Contribution

It provides a simulation-based analysis of how CTA site altitude impacts dark matter search sensitivity, informing optimal site selection.

Findings

Higher altitudes improve detection sensitivity for lower WIMP masses.

Altitude influences the background rejection efficiency of CTA.

Optimal site altitude balances sensitivity and observational constraints.

Abstract

Observations of dwarf galaxies and of the Milky Way halo with current ground-based Cherenkov telescopes have resulted in interesting limits on the cross-section for dark matter (DM) self- annihilation for WIMP masses above some 100 GeV. The future Cherenkov Telescope Array (CTA) is expected to further explore the parameter space of dark matter candidates that are predicted in extensions of the standard model of particle physics. Due to its low energy threshold (of order of few tens of GeV) and high sensitivity, CTA will also probe lower WIMP masses than current experiments, but the actual performance in this regime will be influenced by the altitude of the observatory above sea level. Using the response of possible CTA candidate arrays to simulated photons and hadrons, we estimate how searches for a WIMP annihilation signal from the Milky Way halo will be influenced by altitude of different possible CTA sites.