Seminatural gauge mediation from product group unification

Abstract

We propose a focus point gauge mediation model based on the product group unification (PGU), which solves the doublet-triplet splitting problem of the Higgs multiplets. In the focus point gauge mediation, the electroweak symmetry breaking scale can be naturally explained even for multi-TeV stops. It is known that the focus point behavior appears if a ratio of the number of SU (2) doublet messengers to that of SU (3) triplet messengers is close to 5/2. Importantly, this ratio (effectively) appears in our scenario based on the PGU, if the messenger field is an adjoint representation of SU (5) gauge group. Therefore, our focus point scenario is very predictive. It is also pointed out the gravitino can be dark matter without spoiling the success of the thermal leptogenesis.

Low fine-tuning in Yukawa-deflected gauge mediation

“…This is due to different effects: the new contributions to the stop soft masses in Eqs. (8,9) are negative for λ t 0.7 [34]; a sizable A t (generated at 1-loop ∝ λ 2 t ) allows for m h ≈ 125 GeV with a lighter stop sector and, at the same time, lowers the mass of the lightest stop eigenstate through a large LR stop mixing. As a result, we find the lowest values of ∆ EW for λ t ≈ 0.6 ÷ 0.8, as shown in the bottom-right plot of Hu .…”

“…Eqs. (8)(9)(10)(11)(12), in particular to m 2 Hu . We can argue that indeed ∆ BG (λ t ) should not be considered in computing the FT (similarly to ∆ BG (y t )), since λ t is a Yukawa coupling.…”

“…As a consequence a compensation between the two terms, hence a reduced value of | m 2 Hu | at low energies, is possible provided that M 2 > M 3 (as the gluino mass M 3 induces large positive contributions to the stop masses in the running). For related works, see [6][7][8][9][10][11].…”