Light charged fermions in quantum gravity

TL;DR

This paper investigates how quantum gravity influences chiral fermions with gauge charges, potentially affecting fermion masses and chiral symmetry, with implications for particle physics and quantum gravity theories.

Contribution

It explores the interplay between quantum gravity, gauge interactions, and fermion mass generation, revealing conditions for fermion lightness and chiral symmetry breaking.

Findings

Quantum gravity can induce finite gauge couplings.

Fermion lightness is protected for many fermions.

Chiral symmetry may break with fewer fermions.

Abstract

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.