Gravitationally localized states of two neutral fermions interacting with a Higgs field

We present localized 'particle-like' states composed of a pair of neutral fermions interacting with a scalar Higgs field and the metric of spacetime, extending the Einstein-Dirac formalism introduced by Finster, Smoller, and Yau [Phys. Rev. D 59, 104020 (1999)]. We demonstrate that, when the coupling between the fermions and the Higgs field is strong, there is a class of states in which the total (ADM) mass no longer increases proportionally to the mass of the constituent fermions; indeed it decreases. This phenomenon enables fermionic particles with much larger masses than in the Higgs-free case to form localized states.