TeV Particle Astrophysics 2017 (TeVPA 2017)

Enhancing Dark Matter Annihilation Rates with Dark Bremsstrahlung

7 Aug 2017, 16:15

15m

Athenian Room (The Athenaeum)

Oral Dark matter (direct detection, indirect detection, theory, etc.) Dark matter

Speaker

Nicole Bell (University of Melbourne)

Description

Many dark matter interaction types lead to annihilation processes which suffer from $p$-wave suppression or helicity suppression, rendering them sub-dominant to unsuppressed $s$-wave processes. We demonstrate that the natural inclusion of dark initial state radiation can open an unsuppressed $s$-wave annihilation channel, and thus provide the dominant dark matter annihilation process for particular interaction types. We illustrate this effect with the bremsstrahlung of a dark pseudoscalar or vector boson from fermionic dark matter, $\bar{\chi }\chi \to \bar{f}f\varphi$ or $\bar{f}f{Z}^{\prime }$. The dark initial state radiation process, despite having a 3-body final state, proceeds at the same order in the new physics scale $\mathrm{\Lambda }$ as the annihilation to the 2-body final state $\bar{\chi }\chi \to \bar{f}f$. This is lower order in $\mathrm{\Lambda }$ than the well-studied lifting of helicity suppression via Standard Model final state radiation, or virtual internal bremsstrahlung. This dark bremsstrahlung process should influence LHC and indirect detection searches for dark matter.

Presentation materials

TeVPA_darkbrem_Bell_2017.pdf