Dark Photon Bremsstrahlung and Ultra-High-Energy Cosmic Ray

TL;DR

This paper proposes a novel method to detect ultralight dark photons by analyzing energy loss in ultra-high-energy cosmic rays due to dark photon Bremsstrahlung, offering a new observational test for dark matter models.

Contribution

It introduces a new approach to probe dark photons via Bremsstrahlung effects on cosmic rays, providing potential observational limits and expanding dark matter detection strategies.

Findings

Dark photon Bremsstrahlung can cause measurable energy loss in UHECRs.

The method sets new exclusion limits on ultralight dark photon parameters.

Potential to test dark photon models with cosmic ray observational data.

Abstract

A dark photon is a hypothetical particle that is similar to a photon with a small mass and interacts very weakly with ordinary matter through a kinetic mixing with the ordinary photon. In this paper, we propose a new way to probe the existence of dark photons through the Bremsstrahlung effect on ultra-high-energy cosmic rays (UHECRs). Using the standard soft photon calculation, we demonstrate that the dark photon Bremsstrahlung process could lead to significant energy loss for protons in the ultralight dark photon scenario, and that this effect could be tested against observational data of UHECRs. We also provide exclusion limits which can be compared with existing limits on ultralight dark photons.