Flavored gauge-mediation

Abstract

The messengers of Gauge-Mediation Models can couple to standard-model matter fields through renormalizable superpotential couplings. These matter-messenger couplings generate generation-dependent sfermion masses and are therefore usually forbidden by discrete symmetries. However, the non-trivial structure of the standard-model Yukawa couplings hints at some underlying flavor theory, which would necessarily control the sizes of the matter-messenger couplings as well. Thus for example, if the doublet messenger and the Higgs have the same properties under the flavor theory, the resulting messenger-lepton couplings are parametrically of the same order as the lepton Yukawas, so that slepton mass-splittings are similar to those of minimally-flavor-violating models and therefore satisfy bounds on flavor-violation, with, however, slepton mixings that are potentially large. Assuming that fermion masses are explained by a flavor symmetry, we construct viable and natural models with messenger-lepton couplings controlled by the flavor symmetry. The resulting slepton spectra are unusual and interesting, with slepton mass-splittings and mixings that may be probed at the LHC. In particular, since the new contributions are typically negative, and since they are often larger for the first- and second-generation sleptons, some of these examples have the selectron or the smuon as the lightest slepton, with mass splittings of a few to tens of GeV.