6533b86efe1ef96bd12cc074
RESEARCH PRODUCT
Estimating QCD uncertainties in Monte Carlo event generators for gamma-ray dark matter searches
Peter SkandsSascha CaronRoberto Ruiz De AustriSimone AmorosoAdil Jueidsubject
dark matter simulationsParticle physicsCosmology and Nongalactic Astrophysics (astro-ph.CO)PhotonAstrophysics::High Energy Astrophysical Phenomenamodel [hadronization]SLDgamma ray theoryDark matterMonte Carlo methodHadronFOS: Physical sciencesmass [dark matter]01 natural sciencesHigh Energy Physics - Phenomenology (hep-ph)fragmentationquantum chromodynamics0103 physical sciencesconservation lawddc:530High Energy PhysicsMonte Carloenergy spectrum [gamma ray]Quantum chromodynamicsPhysicsdark matter theoryAnnihilation010308 nuclear & particles physicsphotonGamma rayCERN LEP StorAstronomy and AstrophysicsshowersGalaxyHigh Energy Physics - PhenomenologyannihilationExperimental High Energy PhysicsHigh Energy Physics::Experimentgalaxydecay [hadron]GLAST [interpretation of experiments]Astrophysics - Cosmology and Nongalactic Astrophysicsdescription
Motivated by the recent galactic center gamma-ray excess identified in the Fermi-LAT data, we perform a detailed study of QCD fragmentation uncertainties in the modeling of the energy spectra of gamma-rays from Dark-Matter (DM) annihilation. When Dark-Matter particles annihilate to coloured final states, either directly or via decays such as $W^{(*)}\to q\bar{q}'$, photons are produced from a complex sequence of shower, hadronisation and hadron decays. In phenomenological studies, their energy spectra are typically computed using Monte Carlo event generators. These results have however intrinsic uncertainties due to the specific model used and the choice of model parameters, which are difficult to asses and which are typically neglected. We derive a new set of hadronisation parameters (tunes) for the \textsc{Pythia~8.2} Monte Carlo generator from a fit to LEP and SLD data at the $Z$ peak. For the first time, we also derive a conservative set of uncertainties on the shower and hadronisation model parameters. Their impact on the gamma-ray energy spectra is evaluated and discussed for a range of DM masses and annihilation channels. The spectra and their uncertainties are also provided in tabulated form for future use. The fragmentation-parameter uncertainties may be useful for collider studies as well.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-12-18 |