Nonuniversal Gaugino Masses and Natural Supersymmetry

Abstract

We demonstrate that natural supersymmetry is readily realized in the framework of SU (4)c ×SU (2) L ×SU (2) R with nonuniversal gaugino masses. Focusing on ameliorating the little hierarchy problem, we explore the parameter space of this model which yields small fine-tuning measuring parameters (natural supersymmetry) at the electroweak scale (∆ EW ) as well as at high scale (∆ HS ). It is possible to have both ∆ EW and ∆ HS less than 100 in these models, (2% or better fine-tuning), while keeping the light CP-even (Standard Model-like) Higgs mass in the 123-127 GeV range. The light stop quark mass lies in the range 700 GeV < mt 1 < 1500 GeV, and the range for the light stau lepton mass is 900 GeV < mτ 1 < 1300 GeV. The first two family squarks are in the mass range 3000 GeV < mt 1 < 4500 GeV, and for the gluino we find 2500 GeV < mg 1 < 3500 GeV. We do not find any solution with natural supersymmetry which yields significant enhancement for Higgs production and decay in the diphoton channel.

Probing light higgsinos in natural SUSY from monojet signals at the LHC

“…In addition, when µ ≪ M 1,2 , these processes are largely insensitive to other SUSY parameters but higgsino mass µ. Therefore, we do not consider the production of stops and gluino in this paper, which contribute to the fine-tuning in more complicated and model-dependent way [19][20][21][22]. The current constraints on the mass limits of stop and gluino in natural SUSY have been discussed in [28][29][30][31][32][33].…”

“…(1.1), µ and m Hu must be of the order of ∼ 100 − 200 GeV, which implies light higgsinos. At the same time, the electroweak gaugino mass parameters M 1,2 are preferred to be of the similar order as the heavy gluino mass parameter M 3 and large Higgs-stop trilinear coupling A t is JHEP02(2014)049 needed [19][20][21][22]. Hence, generically we have µ ≪ M 1,2 and the mass splittings between the lightest chargino and the lightest two neutralinos at leading order are determined by [27] …”

Non-universal gaugino masses and fine tuning implications for SUSY searches in the MSSM and the GNMSSM

“…It has been observed that this can reduce the hierarchy problem through the appearance of a new "focus point" that makes the Higgs mass less sensitive to the gaugino mass scale [16][17][18][19][20][21][22][23][24][25][26]. Here we explore this possibility in detail for both the MSSM and GNMSSM in the context of the latest LHC bounds on SUSY states and the measurement of the Higgs mass.…”

Probing the hyperbolic branch/focus point region of the constrained minimal supersymmetric standard model with generalized Yukawa quasiunification

“…It is well-known that such a heavy gluino spoils the success of several models which consider the HB/FP region [64][65][66][67][68][69][70][71]. However, as we will show, this does not happen in our case.…”