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

TL;DR

This paper improves predictions of high-energy photon spectra from dark-matter annihilation by combining electroweak resummation with parton-shower models, accounting for Sommerfeld effects, to refine the expected gamma-ray signals.

Contribution

It introduces a method to merge electroweak Sudakov resummation with parton-shower simulations for more accurate gamma-ray spectra from dark matter annihilation.

Findings

Electroweak resummation alters the photon spectrum shape significantly.

The method provides more precise predictions for gamma-ray signals.

Sommerfeld effects are incorporated into the spectrum calculations.

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 $E_\gamma \sim (0.6\ldots 1)\, m_\chi$ and hence the form of the so-called "line-signal".