Anatomy of maximal stop mixing in the MSSM

Abstract

A Standard Model-like Higgs near 125 GeV in the MSSM requires multi-TeV stop masses, or a near-maximal contribution to its mass from stop mixing. We investigate the maximal mixing scenario, and in particular its prospects for being realized it in potentially realistic GUT models. We work out constraints on the possible GUT-scale soft terms, which we compare with what can be obtained from some well-known mechanisms of SUSY breaking mediation. Finally, we analyze two promising scenarios in detail, namely gaugino mediation and gravity mediation with non-universal Higgs masses.

Linking natural supersymmetry to flavour physics

“…Essentially all our phenomenological considerations are the same as in the SU(2) global case. We also point out that in addition to the well known bound on the splitting between the first two and the third family masses [15,[18][19][20], there is in general also an upper bound on the splitting between the left and right handed sbottoms, dependent on the value of tan β. It is a combined effect of the 2-loop and 1-loop contributions to the RG equations for the Higgs mass parameter m 2 H and the scalar masses, mainly the CP-odd Higgs scalar,respectively, that depend on the bottom Yukawa coupling and are proportional to the right-handed sbottom mass.…”

“…It is well known that in models defined at a high scale, the initial splitting of the first two families of squarks (let their mass bem 1,2 ) from the third one (with massm 3 ) cannot be arbitrarily large (see refs. [15,[18][19][20]). This is because of the 2-loop sensitivity to the heavy masses in the RG equations for the Higgs mass parameter m 2…”

Enhanced Higgs mass in a gaugino mediation model without the Polonyi problem

“…If the particle content of the MSSM is assumed up to the cut-off scale (which will be taken to be at the GUT scale), the Higgs mass of around 125 GeV is realized only in the region out of the reach of the LHC experiment [18]. However, we point out that the existence of the extra matters can drastically enhance the trilinear coupling of the stop, even if there are no direct couplings to the MSSM matter fields.…”

“…This paper is organized as follows. In section 2, we explain the setup of our "gaugino dominated SUSY breaking" scenario and show that the Higgs mass of 125 GeV can be consistent only with the gluino mass heavier than about 4 TeV with the particle content of the MSSM [18]. In section 3, we show that the trilinear coupling of the stop is enhanced if the extra matters exist; the Higgs mass can be explained with the gluino mass of 1 − 2 TeV.…”

“…Adapting the uncertainty in the Higgs mass calculation of 2 − 3 GeV [22,23], Higgs mass as large as m h ≃ 125 GeV may be realized if the gluino mass is heavier than about 4 TeV [18]. Unfortunately, such a heavy gluino (and squarks) is out of the reach of the LHC experiments.…”