Flavor changing fermion-graviton vertices

Abstract

We study the flavor-changing quark-graviton vertex that is induced atthe one-loop level when gravitational interactions are coupled to thestandard model. Because of the conservation of the energy-momentumtensor the corresponding form factors turn out to be finite and gaugeinvariant. Analytical expressions of the form factors are provided atleading order in the external masses. We show that flavor-changinginteractions in gravity are local if the graviton is strictly masslesswhile if the graviton has a small mass long-range interactions inducinga flavor-changing contribution in the Newton potential appear.Flavor-changing processes with massive spin-2 particles are alsobriefly discussed. These results can be generalized to the case of thelepton-graviton coupling.