CosmiXs: Improved spectra for dark matter indirect detection

TL;DR

This paper presents enhanced calculations of dark matter annihilation spectra incorporating electroweak effects, helicity information, and improved hadronization modeling, providing more accurate inputs for indirect detection analyses.

Contribution

It introduces a novel approach using helicity-dependent antenna showers and updated fragmentation tuning to improve spectral predictions for dark matter annihilation.

Findings

Inclusion of electroweak radiation effects in spectra calculations.

Implementation of helicity-dependent showering with Vincia.

Public release of spectra for dark matter masses 5-100 GeV.

Abstract

The spectra of stable particles produced from dark matter (DM) are one of the most important ingredients to calculate the fluxes for DM indirect detection experiments. At energies above a few GeV, most of the particles are produced following a complex sequence of phenomena including resonance decays, QED and QCD final-state radiation, radiation of weak gauge bosons, hadronization and hadron decays. In this contribution, we discuss improvements on the calculation of the energy spectra at the source using state-of-the-art tools that include effects that were not taken previously into account. We include helicity information of the particles produced in the annihilation channels, which leads to proper inclusion of electroweak radiation during the entire showering history. These effects are taken into account using the Vincia, which is based on the helicity-dependent antenna shower formalism. Off-shell contributions are also taken into account for annihilation channels into $WW$ and $ZZ$ through the four-body processes into fermions and for DM masses below the gauge boson mass. We also revisit the tune of the Lund fragmentation function parameters in Pythia using LEP data at the $Z$-boson pole. The spectra of cosmic messengers are provided for DM masses between 5 GeV and 100 GeV and are publicly distributed in this \href{https://github.com/ajueid/CosmiXs.git}{GitHub repository}.