title: Gravitational correction to running of gauge couplings.
abstract: We calculate the contribution of graviton exchange to the running of gauge couplings at lowest non-trivial order in perturbation theory. Including this contribution in a theory that features coupling constant unification does not upset this unification, but rather shifts the unification scale. When extrapolated formally, the gravitational correction renders all gauge couplings asymptotically free.
authors.affiliation: Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. spatrick@mit.edu
authors.forename: Sean P
authors.initials: SP
authors.lastname: Robinson
authors.forename: Frank
authors.initials: F
authors.lastname: Wilczek