A Tale of Two $U(1)$'s: Kinetic Mixing from Lattice WGC States

Understand

We point out that the states required by the Lattice Weak Gravity Conjecture, along with certain genericity conditions, imply the existence of non-vanishing kinetic mixing between massless Abelian gauge groups in the low-energy effective theory.

• We carry out a phenomenological estimate using a string-inspired probability distribution for the masses of superextremal states and compare the results to expectations from string theory and field theory, estimating the magnitude of kinetic mixing in each case.
• In the string case, we compute the kinetic mixing in an ensemble of 1858 MSSM-like heterotic orbifolds as well as in Type II supergravity on a Calabi-Yau manifold.
• From the field theory perspective, we consider compactifications of a 5D gauge theory.