https://doi.org/10.1140/epjc/s10052-020-08691-4
Letter
U(1) mixing and the weak gravity conjecture
Laboratoire de Physique Théorique et Hautes Energies (LPTHE), UMR 7589, Sorbonne Université et CNRS, 4 place Jussieu, 75252, Paris Cedex 05, France
Received:
2
August
2020
Accepted:
20
November
2020
Published online:
4
December
2020
Tiny values for gauge couplings of dark photons allow to suppress their kinetic mixing with ordinary photons. We point out that the weak gravity conjecture predicts consequently low ultraviolet cut-offs where new degrees of freedom might appear. In particular, a mixing angle of 
, required in order to fit the excess reported by XENON1T, corresponds to new physics below 
TeV, thus accessible at a future circular collider. We show that possible realizations are provided by compactifications with six large extra dimensions and a string scale of order TeV.
© The Author(s) 2020
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