Searching in the dark: the hunt for the dark photon

TL;DR

This paper reviews the search for dark photons, hypothetical particles mediating a hidden force that could reveal new aspects of dark matter, highlighting recent experimental efforts and their significance.

Contribution

It discusses the theoretical motivation for dark photons and summarizes recent experimental searches, emphasizing their potential to uncover new physics beyond the Standard Model.

Findings

No definitive detection of dark photons yet

Experimental constraints have significantly limited dark photon parameter space

Future experiments could improve sensitivity to discover or exclude dark photons

Abstract

The existence of Dark Matter (DM) is a well established fact since many decades, thanks to the observation of the effects of its gravitational interaction with the ordinary matter in the Universe. However, our knowledge of the Dark Matter features is still rather scarce. Indeed, one of the biggest quests in fundamental science today is the investigation of Dark Matter nature, from its origin to its composition, and the way its constituents interact with the ordinary matter, apart from gravity. Huge and ambitious efforts have been spent in the last years into its identification, concentrating especially on the search of viable Weakly Interacting Massive Particle candidates. However, no positive results have been achieved so far along this direction. On the other hand, many fascinating new ideas and models for its interpretation have been blooming: among them, an intriguing hypothesis is that the Dark Matter constituents could be neutral under Standard Model interactions, but they could interact through a new, still unknown, force under a "hidden" charge. This new hidden symmetry would be mediated by a massive gauge boson, the dark photon, which is expected to couple to the Standard Model via a kinetic mixing. The search for such a massive mediator has been pursued with large enthusiasm and dedication in the latest years, as its observation could be within the reach of many already existing experimental facilities, both based on accelerators