Constraining the Secluded and Catalyzed Annihilation Dark Matter with Fermi-LAT and Planck Data

TL;DR

This paper introduces a dark matter model with a complex scalar and a hidden gauge symmetry, analyzing its relic density and detection constraints, and finds that considering complete annihilation channels weakens previous indirect detection limits.

Contribution

It provides a comprehensive analysis of secluded and catalyzed annihilation scenarios in a scalar dark matter model with hidden gauge interactions, extending to other spins and correcting previous simplified assumptions.

Findings

Weaker indirect detection constraints when including full annihilation channels.

The $U(1)_D imes U(1)_{L_4_4}$ model has the weakest constraints.

Complete calculations reduce the restrictiveness of previous limits.

Abstract

We propose a dark matter (DM) model with a complex scalar charged under a hidden gauge symmetry, denoted as $U(1)_D$. The scalar field is the DM candidate while the $U(1)_D$ gauge field $A'$ plays the role of a mediator, which connects the dark sector to the standard model (SM) sector via a tiny kinetic mixing. We find that both the secluded and catalyzed annihilation scenarios can be realized in this model. The phenomenology of DM, including relic density, indirect detection (Fermi-LAT), and CMB (Planck) constraints, is discussed. We also extend our discussion to DM with other spins, including Dirac fermion and vector boson. Our analysis is carried out in two models, denoted as $U(1)_D \times U(1)_Y$ and $U(1)_D \times U(1)_{L_\mu-L_\tau}$, with the former corresponding to $A'$ kinetically mixing with the $U(1)_Y$ gauge field $B$ and the latter corresponding to $A'$ mixing with the $U(1)_{L_\mu-L_\tau}$ gauge field $Z'$. We find that, in previous studies, the indirect detection limits were overly restrictive because they only considered the simplified $2\mathrm{DM} \to 2\mathrm{SM}$ annihilation channel. In contrast, by performing a complete calculation of the gamma-ray and CMB constraints from the process $2\mathrm{DM} \to 2A' \to 4\mathrm{SM}$ in the models we consider, we observe weaker constraints in both the $U(1)_D \times U(1)_Y$ and $U(1)_D \times U(1)_{L_\mu-L_\tau}$ models, with the $U(1)_D \times U(1)_{L_\mu-L_\tau}$ model being subject to the weakest constraints overall since it involves less hadronic decay processes.