Effect of polarisation and choice of event generator on spectra from dark matter annihilations

Abstract

If indirect detection searches are to be used to discriminate between dark matter particle models, it is crucial to understand the expected energy spectra of secondary particles such as neutrinos, charged antiparticles and gamma-rays emerging from dark matter annihilations in the local Universe. In this work we study the effect that both the choice of event generator and the polarisation of the final state particles can have on these predictions. For a variety of annihilation channels and dark matter masses, we compare yields obtained with Pythia8 and Herwig7 of all of the aforementioned secondary particle species. We investigate how polarised final states can change these results and do an extensive study of how the polarisation can impact the expected flux of neutrinos from dark matter annihilations in the centre of the Sun.We find that differences between the event generators are larger for yields of hadronic end products such as antiprotons, than for leptonic end products. Concerning polarisation, we conversely find the largest differences in the leptonic spectra. The large differences in the leptonic spectra point to the importance of including polarisation effects in searches for neutrinos from dark matter annihilations in the Sun. However, we find that these differences are ultimately somewhat washed out by propagation effects of the neutrinos in the Sun.

Dark matter spectra from the electroweak to the Planck scale

“…• Inclusion of estimated theoretical uncertainties associated with both the DGLAP and parton shower evolution, for the latter see refs. [80][81][82].…”

Dark Matter Spectra from the Electroweak to the Planck Scale

“…• Inclusion of estimated theoretical uncertainties associated with both the DGLAP and parton shower evolution, for the latter see Refs. [71][72][73].…”

MeV to multi-TeV thermal WIMPs: most conservative limits

“…Instead of Pythia one can use other monte-carlo event generators [51][52][53] to obtain the DM induced fluxes of stable SM particles. Such fluxes can be sensitive to the choice of the event generator [54][55][56], and depending on the event generator used, the DM induced e − (e + ) and ν(ν) fluxes may vary up to ∼ 20%, while the gamma-ray fluxes may change by a factor of a few. Such differences are attributed to the QED and electroweak corrections incorporated in Pythia.…”