Low Scale String Theory Benchmarks for Hidden Photon Dark Matter Interpretations of the XENON1T Anomaly

TL;DR

This paper explores how low scale type-IIB string theory can naturally produce hidden photon dark matter with properties that explain the XENON1T low-energy recoil excess, linking string theory models to dark matter detection signals.

Contribution

It provides a minimal string theory parameter space fit to the XENON1T excess and demonstrates the realization of these models in intersecting D-brane frameworks.

Findings

A good fit to the XENON1T excess with hidden photon parameters around 2.8 keV mass and mixing ~10^{-15}

Benchmark points illustrating the string theory origin of the hidden photon properties

Connection between string theory models and observable dark matter signals

Abstract

An excess of low-energy electronic recoil events over known backgrounds was recently observed in the XENON1T detector, where $285$ events are observed compared to an expected $232 \pm 15$ events from the background-only fit to the data in the energy range 1-7 keV. This could be due to the beta decay of an unexpected tritium component, or possibly to new physics. One plausible new physics explanation for the excess is absorption of hidden photon dark matter relics with mass around $2.8$ keV and kinetic mixing of about $10^{-15}$, which can also explain cooling excesses in horizontal-branch (HB) stars. Such small gauge boson masses and couplings can naturally arise from type-IIB low scale string theory. We provide a fit of the XENON1T excess in terms of a minimal low scale type-IIB string theory parameter space and present some benchmark points which provide a good fit to the data. It is also demonstrated how the required transformation properties of the massless spectrum are obtained in intersecting D-brane models.