Yukawa-unified natural supersymmetry

Abstract

Abstract Previous work on t − b − τ Yukawa-unified supersymmetry, as expected from SUSY GUT theories based on the gauge group SO(10), tended to have exceedingly large electroweak fine-tuning (EWFT). Here, we examine supersymmetric models where we simultaneously require low EWFT (“natural SUSY”) and a high degree of Yukawa coupling unification, along with a light Higgs scalar with m h ~ 125 GeV. As Yukawa unification requires large tan β ~ 50, while EWFT requires rather light third generation squarks and low μ ≈ 100 − 250 GeV, B-physics constraints from BR(B → X s γ) and BR(B s → μ + μ −) can be severe. We are able to find models with EWFT Δ ≲ 50 − 100 (better than 1–2% EWFT) and with Yukawa unification as low as R yuk ~ 1.2 (20% unification). The unification is lessened to R yuk ~ 1.3 when B-physics constraints are imposed. We present several Yukawa-unified natural SUSY (YUNS) benchmark points. LHC searches will be able to access gluinos in the lower 1 – 2 TeV portion of their predicted mass range although much of YUNS parameter space may lie beyond LHC14 reach. If heavy Higgs bosons can be accessed at a high rate, then the rare H, A → μ + μ − decay might allow a determination of tan β ~ 50 as predicted by YUNS models. Finally, the predicted light higgsinos should be accessible to a linear e + e − collider with $ \sqrt{s}\sim 0.5 $ TeV.