AbstractTiny 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 $$\mathcal {O}(10^{-15})$$
O
(
10
-
15
)
, required in order to fit the excess reported by XENON1T, corresponds to new physics below $$\mathcal {O}(100)$$
O
(
100
)
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 $$\mathcal {O}(100)$$
O
(
100
)
TeV.
Weak gravity conjecture with large extra dimensions
