Studying QCD modeling of uncertainties in particle spectra from dark-matter annihilation into jets

TL;DR

This paper analyzes QCD uncertainties affecting particle spectra from dark-matter annihilation into jets, providing detailed estimates of perturbative and non-perturbative effects across a wide mass range.

Contribution

It introduces a comprehensive method to quantify QCD uncertainties in dark-matter annihilation spectra, including re-tuning fragmentation functions and estimating perturbative and non-perturbative effects.

Findings

Quantified QCD uncertainties for dark-matter masses from 10 to 10^5 GeV.

Provided tabulated results for various annihilation channels.

Enhanced understanding of modeling uncertainties in dark-matter indirect detection.

Abstract

Motivated by various excesses observed by the Fermi-LAT and AMS collaborations, we perform a detailed analysis of QCD uncertainties on particle spectra from dark-matter annihilation (or decay) into jets. When annihilated to SM particles, the final-state annihilation products undergo various complicated processes such as QED and QCD bremsstrahlung, hadronisation, and hadron decays. These processes contain some intrinsic uncertainties which are usually difficult to model and which are neglected in physical analyses. First, we perform several re-tunings of the fragmentation function parameters. Then, we estimate two kinds of uncertainties: {\it (i)} perturbative from QCD showers and {\it (ii)} non-perturbative from hadronisation function. The results are tabulated for a wide range of dark matter masses, $m_\chi \in [10, 10^5]~{\rm GeV}$, and annihilation channels. They can be found on Zenodo: https://doi.org/10.5281/zenodo.3764809