Hidden photons with Kaluza-Klein towers

TL;DR

This paper explores how hidden photons extending into extra dimensions with Kaluza-Klein towers can influence observable phenomena, highlighting the impact of additional particles on phenomenology in theories beyond the Standard Model.

Contribution

It introduces a toy model of hidden photons in extra dimensions with Kaluza-Klein modes, analyzing their phenomenological implications and constraints.

Findings

Kaluza-Klein modes enable observable interactions without traditional mass generation mechanisms.

Extra particles significantly affect phenomenological constraints.

The model demonstrates the importance of higher-dimensional effects in hidden photon phenomenology.

Abstract

One of the simplest extensions of the Standard Model (SM) is an extra U(1) gauge group under which SM matter does not carry any charge. The associated boson -- the hidden photon -- then interacts via kinetic mixing with the ordinary photon. Such hidden photons arise naturally in UV extensions such as string theory, often accompanied by the presence of extra spatial dimensions. In this note we investigate a toy scenario where the hidden photon extends into these extra dimensions. Interaction via kinetic mixing is observable only if the hidden photon is massive. In four dimensions this mass needs to be generated via a Higgs or Stueckelberg mechanism. However, in a situation with compactified extra dimensions there automatically exist massive Kaluza-Klein modes which make the interaction observable. We present phenomenological constraints for our toy model. This example demonstrates that the additional particles arising in a more complete theory can have significant effects on the phenomenology.