# Dark Sectors from the Hidden Photon Perspective

## TL;DR

This paper reviews dark sectors involving a kinetically mixed $U(1)_X$ gauge symmetry, explores extended models with SM charges, and discusses experimental signatures and implications for dark matter and muon anomalous magnetic moment.

## Contribution

It analyzes the impact of SM charges under the new $U(1)$ symmetry on dark sector phenomenology and collider signatures, extending minimal models to explain both dark matter and muon $(g-2)$ anomalies.

## Key findings

- Gauged $U(1)_{L_-L_}$ can explain $(g-2)_$ and dark matter abundance.
- Extended models predict four-lepton and two-lepton plus missing energy signatures.
- Kinetic mixing and SM charges significantly alter dark sector phenomenology.

## Abstract

The non-observation of dark matter (DM) by direct detection experiments suggests that any new interaction of DM with the Standard Model (SM) should be very weak. One of the simplest scenarios to achieve this is a dark sector that is charged under a new $U(1)_X$ symmetry, which is kinetically mixed with the SM hypercharge $U(1)_Y$. We briefly review the status of such a minimal setup and analyze in a second step how the picture is altered if also SM fields are charged under the new symmetry. We exemplify this for the case of a gauged $U(1)_{L_\mu-L_\tau}$ and show that this allows for a simultaneous explanation of the $(g-2)_\mu$ excess and the DM relic abundance $\Omega_{DM}$. Furthermore, we discuss the potential of four-lepton and two-lepton plus missing energy signatures to test such scenarios.