A weakly interacting dark matter candidate is difficult to detect at high-energy colliders like the LHC, if its mass is close to or higher than a TeV. On the other hand, pair annihilation of such particles may give rise to $e^{+}{e}^{-}$ pairs in dwarf spheroidal galaxies (dSph), which in turn can lead to radio synchrotron signals that are detectable at the upcoming Square Kilometre Array (SKA) telescope within a moderate observation time. We investigate the circumstances under which this complementarity between collider and radio signals of dark matter can be useful in probing physics beyond the standard model of elementary particles. Both particle physics issues and the roles of diffusion and electromagnetic energy loss of the $e^{\pm }$ are taken into account. First, the criteria for detectability of trans-TeV dark matter are analyzed independently of the particle physics model(s) involved. We thereafter use some benchmarks based on a popular scenario, namely, the minimal supersymmetric standard model. It is thus shown that the radio flux from a dSph like Draco should be observable in about 100 h at the SKA, for dark matter masses up to 4–8 TeV. In addition, the regions in the space spanned by astrophysical parameters, for which such signals should be detectable at the SKA, are marked out.

• Received 21 September 2019

DOI:https://doi.org/10.1103/PhysRevD.101.023015

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society