Late time CMB anisotropies constrain mini-charged particles

TL;DR

This paper uses observations of late-time CMB anisotropies, specifically the Sunyaev-Zel'dovich effect in galaxy clusters, to place new constraints on the properties of mini-charged particles by analyzing photon loss due to pair production in magnetic fields.

Contribution

It introduces a novel method to constrain mini-charged particles using CMB anisotropy data from galaxy clusters, providing new bounds on their properties.

Findings

New constraints on mini-charged particles from Coma cluster observations

Photon depletion due to pair production in magnetic fields limits mini-charged particle properties

Method demonstrates the sensitivity of late-time CMB anisotropies to exotic particle physics

Abstract

Observations of the temperature anisotropies induced as light from the CMB passes through large scale structures in the late universe are a sensitive probe of the interactions of photons in such environments. In extensions of the Standard Model which give rise to mini-charged particles, photons propagating through transverse magnetic fields can be lost to pair production of such particles. Such a decrement in the photon flux would occur as photons from the CMB traverse the magnetic fields of galaxy clusters. Therefore late time CMB anisotropies can be used to constrain the properties of mini-charged particles. We outline how this test is constructed, and present new constraints on mini-charged particles from observations of the Sunyaev-Zel'dovich effect in the Coma cluster.