Light Hidden U(1)s from String Theory

TL;DR

This work analyzes hidden U(1) gauge sectors in LARGE volume string compactifications, emphasizing open-string U(1)s on branes and their potential kinetic mixing with the visible sector. It shows how gauge couplings scale with wrapped cycles via $g_i^{-2} = \frac{\tau_i}{2\pi g_s}$ and how kinetic mixing between visible hypercharge and hidden U(1)s arises from perturbative and non-perturbative effects, yielding a baseline $\chi_{ab} \sim \frac{g_a g_b}{16\pi^2}$ when no light bi-charged matter is present. Masses for hidden photons can be generated by the Stückelberg mechanism (with string-scale masses for anomalous U(1)s) or by hidden-Higgs dynamics, with volumes controlling mass scales from $\mathcal{O}(\text{meV})$ to $\mathcal{O}(\text{GeV})$ depending on the string scale. The paper also discusses a mechanism to obtain a smaller $m_{\gamma'}$ via an additional hidden U(1)$'$ and a tunable $|W_0|$, highlighting the potential for experimentally accessible hidden photons within LVS frameworks.

Abstract

The possible masses and kinetic mixings of hidden U(1)s in the LARGE volume scenario are discussed, including the generalisation of the compact manifold to a K3 fibration.

Figures (1)

• Figure 1: Kinetic mixing between the visible U(1) and a U(1) sitting on a collapsed cycle (upper, blue) or a hyperweak U(1) on a LARGE cycle (lower, red) as a function of the string scale.