Abstract
We investigate the effects of messenger-matter mixing on the lightest CP-even Higgs boson mass m(h) in gauge-mediated supersymmetry breaking models. It is shown that with such mixings m(h) can be raised to about 125 GeV, even when the superparticles have sub-TeV masses, and when the gravitino has a cosmologically preferred sub-keV mass. In minimal gauge mediation without messenger-matter mixing, realizing m(h) similar to 125 GeV would require multi-TeV supersymmetry spectrum. The increase in m(h) due to messenger-matter mixing is maximal in the case of messengers belonging to 10 + (10) over bar of SU(5) unification, while it is still significant when they belong to 5 + (5) over bar of SU(5). Our results are compatible with gauge coupling unification, perturbativity, and the unification of messenger Yukawa couplings. We embed these models into a grand unification framework with a U(1) flavor symmetry that addresses the fermion mass hierarchy and generates naturally large neutrino mixing angles. While supersymmetry mediated flavor changing processes are sufficiently suppressed in such an embedding, small new contributions to K-0 - (K-0) over bar mixing can resolve the apparent discrepancy in the CP asymmetry parameters sin 2 beta and epsilon(K).