Light charged fermions in quantum gravity

Understand

We study the impact of quantum gravity on a system of chiral fermions that are charged under an Abelian gauge group.

• Under the impact of quantum gravity, a finite value of the gauge coupling could be generated and in turn drive four-fermion interactions to criticality.
• We find indications that the gravity-gauge-fermion interplay protects the lightness of fermions for a large enough number of fermions.
• On the other hand, for a smaller number of fermions, chiral symmetry may be broken, which would be in tension with the observation of light fermions.