Dark photon constraints using the UHE gamma-ray emission from galactic sources. A Phenomenological Study

TL;DR

This study uses TeV gamma-ray observations from galactic sources to search for dark photons, setting new constraints on their properties due to the absence of observed spectral anomalies.

Contribution

It provides the first constraints on dark photon parameters in the mass range of 10^{-8} to 10^{-5} eV using astrophysical gamma-ray data.

Findings

No significant evidence for dark photons was found.

Established exclusion regions for dark photon mass and mixing angles.

Constraints improve previous bounds in the specified parameter space.

Abstract

Context: Dark photons (Dph) appear in theories beyond the Standard Model of particles (SM). Under certain conditions, it is possible to have a mixing between SM photons and Dphs that should be observed as anomalies in the spectrum of astrophysical sources. Aim: To either find evidence of, or set constraints on the existence of Dphs with masses in the range of $\mu\text{eV}$ using observations of two galactic sources observed at TeV energies. Methods: Using the flux of the Crab Nebula and MGRO J1908+06 at TeV energies reported by HAWC and LHAASO observatories, and assuming a model where Dphs can mix with SM photons in the vacuum; we compute the Test Statistic (TS) to search for evidence of Dphs in the form of variations/attenuation in the observed spectrum. Results: We do not find statistically significant evidence of the existence of $\mu\text{eV}$ Dphs. Then, we compute the 68\% C.L. and 95\% C.L. exclusion regions for Dphs with masses in the range from $10^{-8}$ to $10^{-5}~\text{eV}$ and mixing angles with values between 0.01 and 1.0.