Speaker
Description
In the past decade, indirect searches for particle dark matter with gamma-ray experiments have placed stringent constraints on the annihilation cross section or decay lifetime across a wide range of dark matter masses. These limits depend critically on the astrophysical J factor, which encodes the dark matter distribution in the target and typically dominates the systematic uncertainty. As improved observational data and dynamical modeling revise current J-factor determinations, many published limits risk becoming outdated unless the full analyses are repeated.
We derive an analytic expression that quantifies how limited knowledge of the astrophysical J factor affects upper limits. This expression can be used to update published dark matter limits when revised J-factor estimates become available, without requiring access to the full experimental likelihood. The formalism applies to analyses with both Gaussian and log-normal priors on the J factor and is validated with Monte Carlo simulations and by reproducing published limits.
We further show its extension to the combination of multiple targets, allowing combined limits to be updated using only publicly available limits.
This framework enables existing indirect-detection results to be re-evaluated as astrophysical inputs improve, preserving and extending the scientific value of current and future gamma-ray searches for dark matter.
| Primary Abstract Topic | Experiment: WIMPs |
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