A good fit of the fermion masses and mixings has been found in the minimal renormalizable supersymmetric SO(10). This solution needs a strongly split supersymmetry breaking scenario with gauginos and higgsinos around 100 TeV, sfermions close to 10^14 GeV and a low GUT scale of around 6 10^15 GeV. We predict fast proton decays through SO(10) type of d=6 operators and the leptonic mixing angle theta_13 approximately 0.1.
We study the range of Higgs masses predicted by High-Scale Supersymmetry and by Split Supersymmetry, using the matching condition for the Higgs quartic coupling determined by the minimal field content. In the case of Split Supersymmetry, we compute for the first time the complete next-to-leading order corrections, including two-loop renormalization group equations and one loop threshold effects. These corrections reduce the predicted Higgs mass by a few GeV. We investigate the impact of the recent LHC Higgs searches on the scale of supersymmetry breaking. In particular, we show that an upper b…
The smallness of the baryon asymmetry in our universe is one of the greatest mysteries and may originate from some profound physics beyond the standard model. We investigate the Affleck-Dine baryogenesis in split supersymmetry, and find that the smallness of the baryon asymmetry is directly related to the hierarchy between the supersymmetry breaking squark/slepton masses and the weak scale. Put simply, the baryon asymmetry is small because of the split mass spectrum.
We consider the collider phenomenology of split-supersymmetry models. We show that despite the challenging nature of the signals in these models the long-lived gluino can be discovered with masses in excess of 2 TeV at the LHC. At a future linear collider we will be able to observe the renormalization group effects from split supersymmetry, using measurements of the neutralino and chargino masses and cross sections.
In split supersymmetry, the supersymmetric scalar particles are all very heavy, at least at the order of 10^9 GeV, but the gauginos, Higgsinos, and one of the neutral Higgs bosons remain below a TeV. Here we further split the split supersymmetry by taking the Higgsino mass parameter μto be very large. In this case, the μproblem is avoided and we keep the wino as a dark matter candidate. A crude gauge coupling unification is still preserved. Dark matter signals and collider phenomenology are discussed in this μ-split SUSY scenario. The most interesting dark matter signal is the annihilation int…
We compute the gluino lifetime and branching ratios in Split Supersymmetry. Using an effective-theory approach, we resum the large logarithmic corrections controlled by the strong gauge coupling and the top Yukawa coupling. We find that the resummation of the radiative corrections has a sizeable numerical impact on the gluino decay width and branching ratios. Finally, we discuss the gluino decays into gravitino, relevant in models with direct mediation of supersymmetry breaking.
Split Supersymmetry does not attempt to solve the hierarchy problem, but it assumes a tuning condition for the electroweak scale. We clarify the meaning of this condition and show how it is related to the underlying parameters. Simple assumptions on the structure of the soft terms lead to predictions on tan beta and on the physical Higgs mass.
We investigate gauge coupling unification in higher dimensional GUT models with split supersymmetry. We focus on 5d and 6d orbifold GUTs, which permit a simple solution to several problems of 4D GUTs as well as control over GUT scale threshold corrections. In orbifold GUTs, calculable threshold corrections can raise or lower the prediction for $α_s(M_Z)$ in a way that depends on the location of Higgs fields. On the other hand, split supersymmetry lowers the prediction for $α_s(M_Z)$. Consequently, split supersymmetry changes the preferred location of the Higgs fields in orbifold GUTs. In the s…
We consider a scenario where supersymmetry is broken at a high energy scale, out of reach of the LHC, but leaves a few fermionic states at the TeV scale. The particle content of the low-energy effective theory is similar to that of Split Supersymmetry. However, the gauginos and higgsinos are replaced by fermions carrying the same quantum numbers but having different couplings, which we call fake gauginos and fake higgsinos. We study the prediction for the light-Higgs mass in this Fake Split SUSY Model (FSSM). We find that, in contrast to Split or high-scale supersymmetry, a 126 GeV Higgs boson…
We explore some fundamental differences in the phenomenology, cosmology and model building of Split Supersymmetry compared with traditional low-scale supersymmetry. We show how the mass spectrum of Split Supersymmetry naturally emerges from theories where the dominant source of supersymmetry breaking preserves an $R$ symmetry, characterize the class of theories where the unavoidable $R$-breaking by gravity can be neglected, and point out a new possibility, where supersymmetry breaking is directly communicated at tree level to the visible sector via renormalizable interactions. Next, we discuss…
We consider the collider phenomenology of split-supersymmetry models. Despite the challenging nature of the signals in these models the long-lived gluino can be discovered with masses above 2 TeV at the LHC. At a future linear collider we will be able to observe the renormalization group effects from split supersymmetry on the chargino/neutralino mixing parameters, using measurements of the neutralino and chargino masses and cross sections. This indirect determination of chargino/neutralino anomalous Yukawa couplings is an important check for supersymmetric models in general.
We perform a quantitative study of the neutron and electron electric dipole moments (EDM) in Supersymmetry, in the limit of heavy scalars. The leading contributions arise at two loops. We give the complete analytic result, including a new contribution associated with Z-Higgs exchange, which plays an important and often leading role in the neutron EDM. The predictions for the EDM are typically within the sensitivities of the next generation experiments. We also analyse the correlation between the electron and neutron EDM, which provides a robust test of Split Supersymmetry.
An argument against tolerating finetuning in the Higgs sector is presented, by emphasizing the difference between (well understood) quantum corrections to scalar masses and the (unsolved) problem of the cosmological constant. I also point out that ``split'' supersymmetry, where all scalars except one Higgs boson have masses many orders of magnitude above the weak scale, is not compatible with simple mechanisms of transmitting supersymmetry breaking (gravity, gauge or anomaly mediation), unless a second, independent finetuning of parameters is introduced. This finetuning is required to obtain a…
An upper limit on the masses of scalar superpartners in split supersymmetry is found by considering cosmological constraints on long-lived gluinos. Over most of parameter space, the most stringent constraint comes from big bang nucleosynthesis. A TeV mass gluino must have a lifetime of less than 100 seconds to avoid altering the abundances of D and Li-6. This sets an upper limit on the supersymmetry breaking scale of 10^9 GeV.
Partial Split Supersymmetry with violation of R-parity as a model for neutrino masses is explored. It is shown that at the one-loop level the model can give predictions that are in agreement with all present experimental values for the neutrino sector. An analytical result is that the small solar neutrino mass difference can be naturally explained in the decoupling limit for the heavy Higgs mass eigenstates.
We study an important contribution to the electric dipole moment (EDM) of the electron (or quarks) at the two-loop level due to the $W$-EDM in the recently proposed scenario of split supersymmetry. This contribution is independent of the Higgs mass, and it can enhance the previous estimation of the electron (neutron) EDM by $20-50%$ ($40-90%$). Our formula is new in its analytical form.
We consider orbifold GUTs with N=1 supersymmetry in which the Standard Model (SM) gauge couplings are unified at M_GUT =~ 2 x 10^16 GeV with one of the third family (charged) Yukawa couplings. With split supersymmetry the SM Higgs mass is estimated to be 131 +/- 10 GeV for gauge-top quark Yukawa unification, which increases to 146 +/- 8 GeV for gauge-bottom quark (or gauge-tau lepton) Yukawa unification.
The decoupling of scalar particles in split supersymmetry makes the spectrum of squarks irrelevant for low energy processes. Nevertheless, the structure of the vacuum is sensitive to the spectrum of squarks, even when the supersymmetry breaking scale is large. In this note, we show that in certain regions of the parameter space, squarks could develop radiatively tachyonic masses, thus breaking electric charge and color. We discuss the constraints that follow from the requirement of charge and color conservation, and we comment on the implications for model building.
We present a scenario wherein the anomalous U(1) D-term of string origin triggers supersymmetry breaking and generates naturally a Split Supersymmetry spectrum. When the gaugino and the Higgsino masses (which are of the same order of magnitude) are set at the TeV scale, we find the scalar masses to be in the range (10^6 - 10^8) GeV. The U(1) D-term provides a small expansion parameter which we use to explain the mass and mixing hierarchies of quarks and leptons. Explicit models utilizing exact results of N = 1 suersymmetric gauge theories consistent with anomaly constraints, fermion mass hiera…
We derive in detail a condition on the Higgs mass parameters that is necessary for the recently proposed ``split supersymmetry'' (split SUSY) scenario to provide a realistic magnitude of $\tan β$. The nature of this condition can be understood by showing how the Higgs sector of the minimal supersymmetric Standard Model reduces to that of the Standard Model in the heavy limit of the soft supersymmetry breaking Higgs mass parameters. Based on this condition, we present some simple supersymmetry breaking models that each provides a realistic split-SUSY mass spectrum, in accordance with the scale …
We show that the running of the Higgs-gaugino-higgsino couplings present in Partial Split Supersymmetry can severely affect the neutrino masses generated through Bilinear R-parity Violation. We find a working scenario where the predicted neutrino observables satisfy the experimental constraints when the running is neglected. After including the running, we show that already with a split supersymmetric scale of 10000 GeV the atmospheric mass leaves the allowed experimental window, and that the solar mass leaves it even earlier, with a split supersymmetric scale of 1000 GeV. This shows that the …
It has been proposed recently that, within the framework of split Supersymmetry, long lived gluinos generated in astrophysical sources could be detected using the signatures of the air showers they produce, thus providing a lower bound for their lifetime and for the scale of SUSY breaking. We present the longitudinal profile and lateral spread of $G$-hadron induced extensive air showers and consider the possibility of measuring them with a detector with the characteristics of the Pierre Auger Observatory.
We present an extension of the minimal split supersymmetry model, which is capable of explaining the baryon asymmetry of the Universe. Instead of MSSM we start from NMSSM and split its spectrum in such a way that the low energy theory contains neutral particles, in addition to the content of minimal split supersymmetry. They trigger the strongly first order electroweak phase transition (EWPT) and provide an additional source of CP-violation. In this model, we estimate the amount of the baryon asymmetry produced during EWPT, using WKB approximation for CP-violating sources in diffusion equation…
We examine the possibility of detecting signals of split supersymmetry in the loop-induced decay h --> gamma gamma of the Higgs boson at the Large Hadron Collider, where charginos, as surviving light fermions of the supersymmetric spectrum, can contribute in the loop. We perform a detailed study of uncertainties in various parameters involved in the analysis, and thus the net uncertainty in the standard model prediction of the rate. After a thorough scan of the parameter space, taking all constraints into account, we conclude that it will be very difficult to infer about split supersymmetry fr…
The mass of the Higgs boson in the Split Supersymmetric Standard Model is calculated, including all one-loop threshold effects and the renormalization group evolution of the Higgs quartic coupling through two-loops. The two-loop corrections are very small (<<1 GeV), while the one-loop threshold corrections generally push the Higgs mass down several GeV.
We propose a supersymmetric SU(5) orbifold GUT in 5 dimensions in which supersymmetry breaking at the boundaries give rise to split supersymmetry spectrum. The extra dimension is compactified on a $S^1/Z_2 \times Z_2^\prime$ orbifold having two fixed points. The standard model fermions are localized in the standard model brane, where supersymmetry is broken by the nonvanishing of the F-term of a superfield X at some intermediate scale. All scalar superpartners acquires mass at this stage. The standard model gauginos and higgsinos remain light, since their masses are protected by R-symmetry and…
In split-supersymmetry (split-SUSY), gluino is a metastable particle and thus can freeze out in the early universe. The late decay of such a long-life gluino into the lightest supersymmetric particle (LSP) may provide much of the cosmic dark matter content. In this work, assuming the LSP is gravitino produced from the late decay of the metastable gluino, we examine the WMAP dark matter constraints on the gluino mass. We find that to provide the full abundance of dark matter, the gluino must be heavier than about 14 TeV and thus not accessible at the CERN Large Hadron Collider (LHC).
We study two realisations of the Fake Split Supersymmetry Model (FSSM), the simplest model that can easily reproduce the experimental value of the Higgs mass for an arbitrarily high supersymmetry scale, as a consequence of swapping higgsinos for equivalent states, fake higgsinos, with suppressed Yukawa couplings. If the LSP is identified as the main Dark matter component, then a standard thermal history of the Universe implies upper bounds on the supersymmetry scale, which we derive. On the other hand, we show that renormalisation group running of soft masses above the supersymmetry scale bare…
We update our analysis of the Higgs sector masses in Minimal Supersymmetry and in the Two-Higgs Doublet Model to the final ATLAS and CMS data from the 2011-2012 LHC run.
New version of MSSM scales is discussed. In this version mu << M_{SUSY} ~ M_0 \~ M_{1/2}, where mu is the Higgsino mass, M_0 is the mass scale of sleptons and squarks, M_{1/2} is the mass scale of gaugino. Renormalization group motivation of this MSSM version is proposed. Analysis of Split Supersymmetry ideas in this case together with the Dark Matter arguments results in the statement that the formation of residual neutralino concentration occurs in the high symmetric phase of cosmological plasma. The value of Higgsino mass is estimated. The recharging process for high energy neutralinos in t…
We revive Witten's mechanism for the radiative seesaw induced neutrino masses in SO(10) grand unified theory. We propose its extension to charged fermion masses as a possible cure for wrong tree level mass relations. We offer two simple realizations that can produce a realistic fermionic spectrum. The first one requires two 10 dimensional Higgses in the Yukawa sector and utilizes radiative effects for charged fermion masses. The second one trades one 10 for a 120 dimensional Higgs and leads to the SO(10) theory with less parameters in the Yukawa sector. The mechanism works only if supersymmetr…
We suggest a natural split mechanism for sfermions based on $N$=2 supersymmetry (SUSY). $N$=2 SUSY protects a sfermion in an $N$=2 multiplet from gaining weight by SUSY breaking. Therefore, if partly $N$=2 SUSY is effectively obtained, a split spectrum can be realized naturally. As an example of the natural split mechanism, we build a gauge-mediated SUSY breaking-like model assuming $N$=2 SUSY is partly broken in a UV theory. The model explains the Higgs boson mass and the muon anomalous magnetic dipole moment within $1~σ$ level with a splitting sfermion spectrum. The model has seven light spa…
Radiative neutralino decay $χ^0_2 -> χ^0_1γ$ is studied in a Split Supersymmetric scenario, and compared with mSUGRA and MSSM. This 1-loop process has a transition amplitude which is often quite small, but has the advantage of providing a very clear and distinct signature: electromagnetic radiation plus missing energy. In Split Supersymmetry this radiative decay is in direct competition with the tree-level three-body decay $χ^0_2 -> χ^0_1 f\overline f$, and we obtain large values for the branching ratio $B(χ^0_2 -> χ^0_1γ)$ which can be close to unity in the region $M_2 \sim M_1$. Furthermore,…
We discuss consequences of flavor mixings in the scalar fermion sector of supersymmetric models endowed with ultra heavy scalars. We find that, under extreme fine-tunings different than but similar in size to that needed to obtain a light Higgs doublet, intergenerational mixings generically lead to light sfermion states which facilitate a number of phenomena ranging from rare processes to electric dipole moments. The number of scalar fermions to be discovered by collider searches is fewer than those in a complete supersymmetric model.
Nonobservation of superparticles till date, new Higgs mass limits from the CMS and ATLAS experiments, WMAP constraints on relic density, various other low energy data, and the naturalness consideration, all considered simultaneously imply a paradigm shift of supersymmetric model building. In this paper we perform, for the first time, a detailed numerical study of brane-world induced supersymmetry breaking for both minimal and next-to-minimal scenarios. We observe that a naturally hierarchical spectrum emerges through an interplay of bulk, brane-localized and quasi-localized fields, which can g…
The prospects of detecting neutral Higgs bosons in the minimal supersymmetric model via their decays into muon pairs at the LHC are investigated. The CMS detector performance is adopted for a realistic study of observability. It is found that the muon pair decay mode might provide a very promising channel to search for the neutral Higgs bosons of minimal supersymmetry. This channel will allow precise mass reconstruction for neutral Higgs bosons.
Split supersymmetry is characterized by relatively light chargino and neutralino sector and very heavy sfermion sector. We study the consequence of CP violation in this scenario by evaluating two-loop contributions to electric dipole moments of fermions from Higgs-photon as well as $W$-$W$ diagrams. These contributions add coherently and produce electron and neutron electric dipole moments close to present bounds. We then explore Higgs production at a photon-photon collider, and consider the feasibility of measuring CP violating $hγγ$ coupling induced by chargino loops. Methods of enhancing th…
We investigate the possibility to generate neutrino masses in the context of Split supersymmetric scenarios where all sfermions are very heavy. All relevant contributions coming from the R-parity violating terms to the neutrino mass matrix up to one-loop level are computed, showing the importance of the Higgs one-loop corrections. We conclude that it is not possible to generate all neutrino masses and mixings in Split SUSY with bilinear R-Parity violating interactions. In the case of Partial Split SUSY the one-loop Higgs contributions are enough to generate the neutrino masses and mixings in a…
We discuss neutrino parameters in addition with the effects of a Higgs boson of mass $\sim$ 125 GeV in Split Supersymmetry with Bilinear R-Parity Violation. This model allows for the explanation of neutrino masses and mixing angles, and has the gravitino as Dark Matter candidate. We find constraints on the parameters in the neutrino sector of the model by performing a numerical study of the parameter space, and by fitting neutrino oscillation observables and the Higgs mass. In addition, we study in detail the decay of the lightest neutralino in this model and we realize the importance of the e…
The phenomenological consequences of the dilaton-type soft supersymmetry breaking terms in the context of the next to minimal supersymmetric standard model are investigated. We always find a very low top quark mass. As a consequence such string vacua are excluded by recent experimental results. The viability of the solution of the $μ$ term through the introduction of a gauge singlet field is also briefly discussed.
Motivated by the observation that the Higgs quartic coupling runs to zero at an intermediate scale, we propose a new framework for models of split supersymmetry, in which gauginos acquire intermediate scale Dirac masses of $\sim 10^{8-11}$ GeV. Scalar masses arise from one-loop finite contributions as well as direct gravity-mediated contributions. Like split supersymmetry, one Higgs doublet is fine-tuned to be light. The scale at which the Dirac gauginos are introduced to make the Higgs quartic zero is the same as is necessary for gauge coupling unification. Thus, gauge coupling unification pe…
The contribution to the decay $b\to s γ$ in the Minimal Supersymmetric Standard Model with radiative electroweak breaking is presented. The impact of a detection of this inclusive decay at the SM level is discussed. Results for other inclusive $b-s$ transitions are also mentioned.
Split supersymmetry scenarios with PeV-scale scalar masses circumvent many of the restrictions on supersymmetry coming from experimental limits on CP violation, flavor-changing neutral currents, and the Higgs boson mass. We consider the situation where the LSP is either a Wino or Higgsino and the majority of its cold dark matter relic density is of thermal origin, in which case its mass is specified to be 2.3 TeV for a Wino or 1.1 TeV for a Higgsino. We examine the potential for indirect detection, at present and future gamma-ray telescopes, of the monoenergetic photon lines that would result …
In the recently proposed `split supersymmetry' scenario, the squark and slepton masses are allowed to be at a high scale while the gauginos and Higgsinos are within a TeV. We show that in a theory with broken R-parity, the parameter space of such a scenario allows a situation where the lightest neutralino is still stable on the cosmological scale and can be a dark matter candidate. We also separate the cases where (a) it may be invisible but not a dark matter candidate, or (b) it may decay showing a displaced vertex. It is also emphasized how the constraint on the simultaneous violation of bar…
Radiative corrections to neutrino mixings in seesaw models depend on the nature of new physics between the weak and the GUT-seesaw scales and can be taken into account using the renormalization group equations. This new physics effect becomes particularly important for models with quasi-degenerate neutrino masses where small neutrino mixings at the seesaw scale can get magnified by radiative renormalization effects alone to match observations. This mechanism of radiative magnification which provides a simple understanding of why lepton mixings are so different from quark mixings was demonstrat…
We analyze a simple Split Supersymmetry scenario where fermion masses come from anomaly mediation, yielding m_s ~ 1000 TeV, m_{3/2} ~ 100 TeV, and m_f ~ 1 TeV. We consider non-thermal dark matter production in the presence of moduli, and we find that the decay chains of moduli to LSPs and moduli to gravitinos to LSPs generate dark matter more efficiently than perturbative freeze-out, allowing for a light, LHC visible spectrum. These decaying moduli can also weaken cosmological constraints on the axion decay constant. With squark masses of order 1000 TeV, LHC gluinos will decay millimeters from…
We study the possibilities for the indirect detection of dark matter in Split Supersymmetry from gamma-rays, positrons, and antiprotons. The most promising signal is the gamma-ray line, which may be observable at the next generation of detectors. For certain halo profiles and a high mass neutralino, the line can even be visible in current experiments. The continuous gamma-ray signal may be observable, if there is a central spike in the galactic halo density. The signals are found to be similar to those in MSSM models. These indirect signals complement other experiments, being most easily obser…
We analyze CP violation in supersymmetry with Effective Minimal Flavour Violation, as recently proposed in arXiv:1011.0730. Unlike the case of standard Minimal Flavour Violation, we show that all the phases allowed by the flavour symmetry can be sizable without violating existing Electric Dipole Moment constraints, thus solving the SUSY CP problem. The EDMs at one and two loops are precisely analyzed as well as their correlations with the expected CP asymmetries in B physics.
Assuming that supersymmetry exists well above the weak scale, we derive the full one-loop matching conditions between the SM and the supersymmetric theory, allowing for the possibility of an intermediate Split-SUSY scale. We also compute two-loop QCD corrections to the matching condition of the Higgs quartic coupling. These results are used to improve the calculation of the Higgs mass in models with high-scale supersymmetry or split supersymmetry, reducing the theoretical uncertainty. We explore the phenomenology of a mini-split scenario with gaugino masses determined by anomaly mediation. Dep…
We consider a large number of pair production processes at future colliders (LHC, ILC) for values of the c.m. energy in the TeV range, where a logarithmic expansion of Sudakov kind would provide a reliable description of Split supersymmetric electroweak effects. We calculate all the leading and next to leading terms of the expansions, that would differ drastically in the considered domain from those of an extreme "light" scenario. We imagine then two possible competitive future situations, at LHC and at ILC, where the determination of the energy dependence of the cross sections of certain proc…
We discuss charged lepton flavor violation in supersymmetric models with extended leptonic sectors at low energies. Contrary to the usual high-scale realizations of the seesaw mechanism, these non-minimal supersymmetric models have new superfields and/or interactions at the supersymmetric scale. As a consequence of this, the resulting lepton flavor violating phenomenology may be very different from that of minimal models.
An analysis of electroweak corrections to the anomalous dipole moments of lepton from some special two-loop diagrams where a closed neutralino/chargino loop is inserted into relevant one-loop diagrams of the standard model is presented in the split supersymmetry scenarios. Considering the translational invariance of the inner loop momenta and the electromagnetic gauge invariance, we get all dimension 6 operators and their coefficients. After applying equations of motion to the external leptons, we obtain the anomalous dipole moments of lepton. The numerical results imply that there is paramete…
We compute corrections to precision electroweak observables in supersymmetry in the limit that scalar superpartners are very massive and decoupled. This leaves charginos and neutralinos and a Standard Model-like Higgs boson as the only states with unknown mass substantially affecting the analysis. We give complete formulas for the chargino and neutralino contributions, derive simple analytic results for the pure gaugino and higgsino cases, and study the general case. We find that in all circumstances, the precision electroweak fit improves when the charginos and neutralinos are near the curren…
We implement non-minimal flavour violation (NMFV) in the MSSM at low scale. In this framework, we propose benchmark points for the mSUGRA scenario including non-minimal flavour violation by evaluating a number of experimental low-energy, electroweak precision and cosmological constraints. We finally discuss phenomenological aspects of our NMFV scenario and present a numerical analysis of squark and gaugino production cross sections at the LHC.
The ansatz of vanishing A and B parameters eliminates CP violating complex phases in soft supersymmetry-breaking parameters of the minimal supersymmetric standard model, and thus provides a simple solution to the supersymmetry CP problem. Phenomenological implications of this ansatz are investigated in the framework of minimal supergravity. We show that electroweak symmetry breakdown occurs, predicting relatively large \tan β. The ansatz survives the Higgs mass bound as well as the b \to s γconstraint if the universal gaugino mass is larger than 300 GeV. We also find that the supersymmetric co…
In some models of thermal relic dark matter, the relic abundance may be set by inelastic scattering processes (rather than annihilations) becoming inefficient as the universe cools down. This effect has been called coscattering. We present a procedure to numerically solve the full momentum-dependent Boltzmann equations in coscattering, which allows for a precise calculation of the dark matter relic density including the effects of early kinetic decoupling. We apply our method to a simple model, containing a fermionic SU(2) triplet and a fermionic singlet with electroweak-scale masses, at small…
The naturalness criterion applied to the cosmological constant implies a new-physics threshold at 10^-3 eV. Either the naturalness criterion fails, or this threshold does not influence particle dynamics at higher energies. It has been suggested that the Higgs naturalness problem may follow the same fate. We investigate this possibility and, abandoning the hierarchy problem, we use unification and dark matter as the only guiding principles. The model recently proposed by Arkani-Hamed and Dimopoulos emerges as a very interesting option. We study it in detail, analysing its structure, and the con…
We investigate the limits on the higgs mass in variations of Split Supersymmetry, where the boundary value of the Higgs quartic coupling at the SUSY breaking scale ($m_s$) is allowed to deviate from its value in the minimal model of Arkani-Hamed and Dimopoulos. We show that it is possible for $λ(m_s)$ to be negative and use vacuum stability to put a lower bound on this coupling, and hence on the mass of the physical higgs. We also use the requirement of perturbativity of all couplings up to the cutoff to determine an upper limit for the higgs mass in models which are further modified by additi…
We study various modifications to the minimal models of gauge mediated supersymmetry breaking. We argue that, under reasonable assumptions, the structure of the messenger sector is rather restricted. We investigate the effects of possible mixing between messenger and ordinary squark and slepton fields and, in particular, violation of universality. We show that acceptable values for the $μ$ and $B$ parameters can naturally arise from discrete, possibly horizontal, symmetries. We claim that in models where the supersymmetry breaking parameters $A$ and $B$ vanish at tree level, $\tanβ$ could be l…
In the context of split supersymmetry, the gaugino mass spectrum seems to be very important to satisfy the dark matter content of the universe and the gauge coupling unification. In this paper, we have considered various sources of gaugino masses in the context of unified models. We show that the gaugino mass spectrum varies in different unification pictures. In the context of SU(5), we have found that the Bino/Wino mass ratio can be close to one at the weak scale which is helpful to satisfy the WMAP data. The gluino/Wino mass ratio is also different from the usual scenario of unified gaugino …
