This paper is divided into two parts.In the first part we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the GUT scale. We perform a global χ 2 analysis including the observablesThe fit is performed in the MSSM in terms of 9 GUT scale parameters, while tan β and µ are fixed at the weak scale. Good fits suggest an upper bound on the gluino mass, Mg 2 TeV. This constraint comes predominantly from fitting the bottom quark and Higgs masses (assuming a 125 GeV Higgs). Gluinos should be visible at the LHC in the 14 TeV run but they cannot be described by the typical simplified models. This is because the branching ratios forg → ttχ 0 1,2 , bbχ 0 1,2 , tbχ − 1,2 , btχ + 1,2 , gχ 0 1,2,3,4 are comparable. Stops and sbottoms may also be visible. Charginos and neutralinos can be light with the LSP predominantly bino-like. In the second part of the paper we analyze a complete three family model and discuss the quality of the global χ 2 fits and the differences between the third family analysis and the full three family analysis for overlapping observables. We note that the light Higgs in our model couples to matter like the Standard Model Higgs. Any deviation from this would rule out this model.

LHC searches for fermionic top partners T focus on three decay topologies: T → bW , T → tZ, and T → th. However, top partners may carry new conserved quantum numbers that forbid these decays. The simplest possibility is a conserved parity, under which the top partner is odd and all SM states are even. In this case, decays of top partners may involve new particle-odd scalars, leading to signal topologies more commonly associated with supersymmetry, either with or without R-parity conservation. We study a simplified model in which this possibility is realized, and estimate the bounds on the top partner mass in this model implied by LHC searches for supersymmetry. We find that the bounds can be significantly weaker than in the conventional top partner decay scenario. For example, if the new parity is exact, a 500 GeV top partner is allowed as long as the lightest parity-odd scalar mass is between 325 and 500 GeV. The lower allowed top partner mass reduces the need for fine-tuning in the Higgs mass parameter, compared to the conventional decay scenario. We also present an explicit model, the Oddest Little Higgs, which exhibits this phenomenology.

In this letter we analyze the consequences, for the LHC, of gauge and third family Yukawa coupling unification with a particular set of boundary conditions defined at the GUT scale, which we characterize as effective "mirage" mediation. We perform a global χ 2 analysis including the, BR(B s → µ + µ − ) andThe fit is performed in the MSSM in terms of 10 GUT scale parameters, while tan β and µ are fixed at the weak scale. We find good fits to the low energy data and a SUSY spectrum which is dramatically different than previously studied in the context of Yukawa unification. Gauge coupling unification in supersymmetric grand unified theories (SUSY GUTs) [1][2][3][4][5][6] provides an experimental hint for low energy SUSY. However, it does not significantly constrain the spectrum of supersymmetric particles. On the other hand, it has been observed that Yukawa coupling unification for the third generation of quarks and leptons in models, such as SO(10) or SU(4) c × SU(2) L × SU(2) R , can place significant constraints on the SUSY spectrum in order to fit the top, bottom and tau masses [7][8][9][10][11]. These constraints depend on the particular boundary conditions for sparticle masses chosen at the GUT scale (see for example, [9,[12][13][14], which consider different GUT scale boundary conditions). In this letter we consider effective "mirage" mediation boundary conditions and show that they are consistent with gauge and Yukawa coupling unification with a dramatically different low energy SUSY spectrum. The GUT scale boundary conditions are given by an effective "mirage" pattern with gaugino masses defined in terms of two parameters, M 1/2 an overall mass scale and α the ratio of the anomaly mediation to gravity mediation contribution [15][16][17][18]. Scalar masses are given in terms of m 16 (for squarks and sleptons) and m 10 (for Higgs doublets). In addition, the H u and H d masses are split, either with "Just-So" splitting or with a U(1) D-term which affects all scalar masses. Note, as in Ref.[18], we allow for several origins of SUSY breaking. For example, the dilaton and conformal compensator fields break SUSY at a scale of order M 1/2 , while the dominant contribution to SUSY breaking is at a scale of order m 3/2 ≥ m 16 ≈ m 10 . We fit the low energy observables,and M h in terms of 12 arbitrary parameters. The low energy sparticle spectrum is imminently amenable to testing at the LHC. Two benchmark points are contained in Table III. Fermion masses and quark mixing angles are manifestly hierarchical. The simplest way to describe this hierarchy is with Yukawa matrices which are also hierarchical. Moreover the most natural way to obtain the hierarchy is in terms of effective higher dimension operators of the form W ⊃ λ 16 3 10 16 3 + 16 3 10 45This version of SO(10) models has the nice features that it only requires small representations of SO(10), has many predictions and can, in principle, find an UV completion in string theory. The only renormalizable term in W is λ 16 3 10 16 3 which gives Yukawa cou...

In this paper we study Yukawa-unified SO(10) SUSY GUTs with two types of SO(10) boundary conditions: (i) universal gaugino masses and (ii) non-universal gaugino masses with effective "mirage" mediation. With these boundary conditions, we perform a global χ 2 analysis to obtain the parameters consistent with 11 low energy observables, including the top, bottom, and tau masses. Both boundary conditions have universal scalar masses and "just so" splitting for the up-and down-type Higgs masses. In these models, the third family scalars are lighter than the first two families and the gauginos are lighter than all the scalars. We therefore focus on the gluino phenomenology in these models. In particular, we estimate the lowest allowed gluino mass in our models coming from the most recent LHC data and compare these to limits obtained using simplified models. We find that the lower bound on M g in Yukawa-unified SO(10) SUSY GUTs is generically ∼1.2 TEV at the 1σ level unless there is considerable degeneracy between the gluino and the LSP, in which case the bounds are much weaker. Hence many of our benchmark points are not ruled out by the present LHC data and are still viable models which can be tested at LHC 14.

We consider a 6-dimensional supersymmetric SU(6) gauge theory and compactify two extra-dimensions on a multiply-connected manifold with non-trivial topology. The SU(6) is broken down to the Standard Model gauge groups in two steps by an orbifold projection (or Wilson line), followed by a Wilson line. The Higgs doublets of the low energy electroweak theory come from a chiral adjoint of SU(6). We thus have gauge-Higgs unification. The three families of the Standard Model can either be located in the 6D bulk or at 4D N=1 supersymmetric fixed points.We calculate the Kaluza-Klein spectrum of states arising as a result of the orbifolding. We also calculate the threshold corrections to the coupling constants due to this tower of states at the lowest compactification scale. We study the regions of parameter space of this model where the threshold corrections are consistent with low energy physics. We find that the couplings receive only logarithmic corrections at all scales. This feature can be attributed to the large N=2 6D SUSY of the underlying model.