Low scale string theory benchmarks for hidden photon dark matter interpretations of the XENON1T anomaly

Athanasios Karozas,Stephen F King,George K Leontaris,Dimitrios K Papoulias

doi:10.1103/physrevd.103.035019

Athanasios Karozas, Stephen F King + Show 2 more

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https://doi.org/10.1103/physrevd.103.035019

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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.

Highlights

The XENON Collaboration has reported an excess of low-energy electronic recoil events over known backgrounds in the XENON1T detector, where 285 events are observed compared to an expected 232 Æ 15 events from the background-only fit to the data in the energy range 1–7 keV [1]
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
In this brief note we have focused on the hidden photon interpretation of the XENON1T excess, which seems to be very plausible for a number of reasons, not least of which is that a hidden photon dark matter relic with the mass around 2.8 keV and a kinetic mixing of about 10−15 can explain the XENON1T excess but can explain cooling excesses in HB stars

Summary

INTRODUCTION

The XENON Collaboration has reported an excess of low-energy electronic recoil events over known backgrounds in the XENON1T detector, where 285 events are observed compared to an expected 232 Æ 15 events from the background-only fit to the data in the energy range 1–7 keV [1]. The authors in [36], starting from a type-I string theory background have shown that obtaining such small values of masses and couplings for a directly coupling Z0 is challenging They stressed that small kinetic mixing ( discussed in [37]) may be possible in string theory, which provides further theoretical motivation for the hidden photon explanation of the XENON1T excess. Appendix provides additional details for model building in the context of intersecting D-branes

HIDDEN PHOTONS

LOW SCALE TYPE-IIB STRING THEORY

D-BRANE CONFIGURATIONS

FIT TO THE XENON1T SIGNAL

CONCLUSIONS