Quantum Decoherence of Photons in the Presence of Hidden U(1)s

TL;DR

This paper investigates how quantum decoherence could cause photons to convert into hidden photons in theories with hidden U(1) gauge groups, and finds strong observational constraints on such effects from cosmological and astrophysical data.

Contribution

It demonstrates that quantum decoherence effects leading to photon-hidden photon conversion are tightly constrained by CMB and supernova observations, especially for Planck-scale suppressed decoherence scales.

Findings

Decoherence scales D ~ E^2/M_Pl are incompatible with hidden U(1)s.

Bounds on decoherence are four orders of magnitude stronger than neutrino-based bounds.

Observational data significantly limit the parameter space for hidden sector models.

Abstract

Many extensions of the standard model predict the existence of hidden sectors that may contain unbroken abelian gauge groups. We argue that in the presence of quantum decoherence photons may convert into hidden photons on sufficiently long time scales and show that this effect is strongly constrained by CMB and supernova data. In particular, Planck-scale suppressed decoherence scales D ~ E^2/M_Pl (characteristic for non-critical string theories) are incompatible with the presence of even a single hidden U(1). The corresponding bounds on the decoherence scale are four orders of magnitude stronger than analogous bounds derived from solar and reactor neutrino data and complement other bounds derived from atmospheric neutrino data.