Matching resummed endpoint and continuum $\gamma$-ray spectra from dark-matter annihilation

Abstract

For the minimal wino and Higgsino benchmark models we provide accurate energy spectra of high-energy photons from TeV scale dark-matter annihilation $\chi \chi \to \gamma +X$ by merging electroweak Sudakov resummation near maximal energy with the electroweak parton-shower PPPC4DM, and accounting for the Sommerfeld effect. Electroweak resummation significantly changes the shape of the photon-energy spectrum in the wide range $E_{\gamma }\sim (0.6\dots 1)m_{\chi }$ and hence the form of the so-called "line-signal".

Comments: 18 pages, 5 figures, ancillary code DM$\gamma$Spec available at https://dmyspec.hepforge.org/