Cosmological constraints on dark matter annihilation and decay: Cross-correlation analysis of the extragalactic $\gamma$-ray background and cosmic shear

TL;DR

This study uses cross-correlation of gamma-ray background and cosmic shear data to set new limits on dark matter annihilation and decay, improving previous constraints and testing specific models like wino dark matter.

Contribution

It introduces an improved analysis method combining gamma-ray and weak lensing data with updated simulations to constrain dark matter properties.

Findings

No significant cross-correlation detected, leading to strong constraints.

Excluded annihilation cross-sections around 10^{-23} cm^3/s for TeV dark matter.

Excluded decay lifetimes around 10^{25} seconds for TeV dark matter.

Abstract

We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of $\sim660$ squared degrees in total. We improve upon our previous analyses by using an updated extragalactic $\gamma$-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological $N$-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of $\sim100$ in the mass range of O(1) TeV when including contributions from secondary $\gamma$ rays due to the inverse-Compton upscattering of background photons. Annihilation cross-sections of $\langle \sigma v \rangle \sim 10^{-23}\, {\rm cm}^3/{\rm s}$ are excluded for TeV-scale DM depending on channel. Lifetimes of $\sim 10^{25}$ sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.