I explore the phenomenology of Supersymmetry models in which the gauginos are much heavier then that scalar particles of the MSSM. In these models, the gauginos are inaccessible to colliders while the scalar spectrum is compressed. I give several examples of models which exhibit this phenomenology built in the class of General Gauge Mediated Models. I explore possible LSP and NLSP candidates in these scenarios including Higgsino, stau, and sneutrino candidates. Collider signatures for these models include multi-particle decay chains, many taus in the final state, and possible displaced vertices with semi-long lived sparticles. I enumerate the most likely collider smoking gun collider signatures for each general LSP/NLSP scenario.
Grand unified theories (GUTs) can lead to non-universal gaugino masses at the unification scale. We study the implications of such non-universal gaugino masses for the composition of the lightest neutralino in supersymmetric (SUSY) theories based on SU(5) gauge group. We also consider the phenomenological implications of non-universal gaugino masses for the phenomenology of Higgs bosons in the context of Large Hadron Collider.
When SUSY breaking produces only dimension-2 terms in the minimal supersymmetric standard model, the parameters of the theory can be rather well constrained. This paper deals with strategies for the detection of the new hadrons predicted in the 1-3 GeV mass range. Some limits are obtained. New signatures for squarks are also given. Squark masses as small as 45 GeV are not yet excluded.
In the axionic solution of the strong CP problem, fermions which transform under quantum chromodynamics (QCD) are required. In supersymmetry, by equating U(1)_{PQ} with U(1)_R, the natural candidates are the gluinos, as pointed out some years ago. A new specific implementation of this idea is proposed, linking the gluino axion scale to that of the canonical seesaw mechanism for neutrinos. Gaugino masses are generated dynamically and the A term is predicted to be very small.
I consider models with non-universal gaugino masses at the gauge coupling unification scale, taking into account the Higgs boson discovery. Viable regions of parameter space are mapped and studied in the case of non-universality following from an F-term in a linear combination of singlet and adjoint representations of SU(5). I consider, in particular, "semi-natural" models that have small μ, with gaugino masses dominating the supersymmetry breaking terms at high energies. Higgsino-like particles are then much lighter than all other superpartners, and the prospects for discovery at the Large Ha…
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.
Gaugino masses might provide useful information on the underlying scheme of supersymmetry breaking as they are least dependent on the unknown physics between the TeV scale and the high messenger scale of supersymmetry breaking. We discuss the pattern of low energy gaugino masses in various schemes of supersymmetry breaking together with the possibility to determine the gaugino masses at LHC.
It has been claimed that Dirac gaugino masses are necessary for realistic models of low-scale supersymmetry breaking, and yet very little attention has been paid to the phenomenology of a light gravitino when gauginos have Dirac masses. We begin to address this deficit by investigating the couplings and phenomenology of the gravitino in the effective Lagrangian approach. We pay particular attention to the phenomenology of the scalar octets, where new decay channels open up. This leads us to propose a new simplified effective scenario including only light gluinos, sgluons and gravitinos, allowi…
I consider models in which non-standard supersymmetry breaking terms, including Dirac gaugino masses, arise from F-term breaking mediated by operators with a $1/M^3$ suppression. In these models, the supersoft properties found in the case of D-term breaking are absent in general, but can be obtained as a special case that is a fixed point of the renormalization group equations. The $μ$ term is replaced by three distinct supersymmetry-breaking parameters, decoupling the Higgs scalar potential from the Higgsino masses. Both holomorphic and non-holomorphic scalar cubic interactions with minimal f…
I explore an economical variant on supersymmetric standard models which may be indicated on cosmological grounds and is shown to have no SUSY-CP problem. Demanding radiative electroweak symmetry breaking suggests that the Higgs is light; other scalar masses may be ~ 100-200 GeV or less. In this case the gluino and photino, while massless at tree level, have 1-loop masses m(gluino) ~ 100 - 600 MeV and m(photino) ~ 100 - 1000 MeV. New hadrons with mass ~ 1 - 3 GeV are predicted and their lifetimes estimated. Existing experimental limits are discussed.
The light gaugino scenario predicts that the lighter chargino mass is less than m_W, gluino and lightest neutralino masses are <~ 1 GeV, and the dominant decay mode of charginos and non-LSP neutralinos is generically to three jets. The excess "4j" events observed by ALEPH in e+ e- annihilation at 133 GeV may be evidence that m(C_1) = 53 GeV. If so, m(N_2) = 110-121 GeV, m(N_2) = 38-63 GeV, m(N_3) = 75-68 GeV; m(sneu_e) is probably ~m(C_1). A detailed analysis of the multi-jet events is needed to exclude this possibility. Consequences for FNAL and higher energy LEP running are given.
We present an extensive analysis of squark and gaugino hadroproduction and decays in non-minimal flavour violating supersymmetry. We employ the so-called super-CKM basis to define the possible misalignment of quark and squark rotations, and we use generalized (possibly complex) charges to define the mutual couplings of (s)quarks and gauge bosons/gauginos. The cross sections for all squark-(anti-)squark/gaugino pair and squark-gaugino associated production processes as well as their decay widths are then given in compact analytic form. For four different constrained supersymmetry breaking model…
We investigate squark and gluino pair production at LHC (CMS) with subsequent decays into quarks, leptons and LSP in models with effective supersymmetry where third generation of squarks is relatively light while the first two generations of squarks are heavy. We consider the general case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in $(n \geq 2)jets + (m \geq 0)leptons + E^{miss}_T$ events depends rather strongly on the relation between LSP, second neutralino, gluino and squark masses and it decreases with the increase of LSP mass.
The tree-level-massless gaugino scenario predicts that the lighter chargino mass is less than m_W and that gluino and lightest neutralino masses are $\lsi 1$ GeV. In this case the dominant decay mode of charginos and non-LSP neutralinos is generically to three jets. The excess of "4j" events with total invariant mass $\sim 105$ GeV observed in LEP running at 130-136 GeV is noted to be consistent with pair production of $\sim 53$ GeV charginos. Data at 161 and 172 GeV from Fall, 1996, cannot conclusively test this hypothesis (because cuts to eliminate $W^+W^-$ background reduce the efficiency s…
Supersymmetry is perhaps most effectively probed at the Tevatron through production and decay of weak gauginos. Most of the analyses of weak gaugino observables require electrons or muons in the final state. However, it is possible that the gauginos will decay primarily to tau leptons, thus complicating the search for supersymmetry. The motivating reasons for high tau multiplicity final states are discussed in three approaches to supersymmetry model building: minimal supergravity, gauge mediated supersymmetry breaking, and more minimal supersymmetry. The concept of ``e/mu/tau candidate'' is in…
In the Next-to-Minimal Supersymmetric Standard Model (NMSSM), the presence of light pseudoscalars can have a dramatic effect on the decays of the Standard Model-like Higgs boson. These pseudoscalars are naturally light if supersymmetry breaking preserves an approximate U(1)_R symmetry, spontaneously broken when the Higgs bosons take on their expectation values. We investigate two classes of theories that possess such an approximate U(1)_R at the mediation scale: deformations of gauge and gaugino mediation. In the models we consider, we find two disjoint classes of phenomenologically allowed pa…
We study the contributions to CP violation in right-handed sneutrino decays induced by soft supersymmetry-breaking gaugino masses including flavour effects and paying special attention to the role of thermal corrections. Using a field-theoretical as well as a quantum mechanical approach we compute the CP asymmetries and we conclude that for all the soft-supersymmetry breaking sources of CP violation considered, an exact cancellation between the asymmetries produced in the fermionic and bosonic channels occurs at T=0 up to second order in soft supersymmetry-breaking parameters. Once thermal eff…
Precision measurements of the Higgs mass have become a powerful constraint on models of physics beyond the standard model. We revisit supersymmetric models with Dirac gauginos and study the contributions to the Higgs mass. We calculate the leading two-loop corrections to the SM-like Higgs mass by constructing a series of EFTs and iteratively integrating out heavy particles. We then apply these calculations to a variety of scenarios, including a simple Dirac gluino, and split Dirac models of supersymmetry. We present the detailed formulae for threshold corrections and compare with previous resu…
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…
Recently, extra dimensional SUSY GUT models have been proposed in which compactification of the extra dimension(s) leads to a breakdown of the gauge symmetry and/or supersymmetry. We examine a particular class of higher-dimensional models exhibiting supersymmetry and SU(5) or SO(10) GUT symmetry. SUSY breaking occurs on a hidden brane, and is communicated to the visible brane via gaugino mediation. Non-universal gaugino masses are developed at the compactification scale as a consequence of a restricted gauge symmetry on the hidden brane. In this case, the compactification scale is at or slight…
The requirement of Yukawa coupling unification highly constrains the SUSY parameter space. In several SUSY breaking scenarios it is hard to reconcile Yukawa coupling unification with experimental constraints from B(b->s gamma) and the muon anomalous magnetic moment a_mu. We show that b-tau or even t-b-tau Yukawa unification can be satisfied simultaneously with b->s gamma and a_mu in the non-universal gaugino mediation scenario. Non-universal gaugino masses naturally appear in higher dimensional grand unified models in which gauge symmetry is broken by orbifold compactification. Relations betwe…
We consider five dimensional supersymmetric warped scenarios in which the Standard Model quark and lepton fields are localized on the ultraviolet brane, while the Standard Model gauge fields propagate in the bulk. Supersymmetry is assumed to be broken on the infrared brane. The relative sizes of supersymmetry breaking effects are found to depend on the hierarchy between the infrared scale and the weak scale. If the infrared scale is much larger than the weak scale the leading supersymmetry breaking effect on the visible brane is given by gaugino mediation. The gaugino masses at the weak scale …
Gaugino condensation in the hidden sector of supergravity models is described within a Nambu-Jona-Lasinio type of approach by minimization of a one-loop scalar potential. The essential ingredients of the mechanism are auxiliary superfields whose v.e.v. generate gaugino condensation and supersymmetry breaking, introduced through Lagrange multipliers. For phenomenologically acceptable values of the gauge couplings, gaugino condensation is disfavoured in this approach. For completeness, it is shown that supersymmetry breaking would occur for a stronger coupling, but at a scale inconsistent with t…
We present a model of supersymmetry breaking which produces gaugino masses and negligible scalar masses at a high scale. The model is inspired by ``deconstructing'' or ``latticizing'' models in extra dimensions where supersymmetry breaking and visible matter are spatially separated. We find a simple four-dimensional model which only requires two lattice sites (or gauge groups) to reproduce the phenomenology.
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 …
We investigate squark and gluino pair production at LHC (CMS) with subsequent decays into quarks, leptons and LSP in models with effective supersymmetry where third generation of squarks is relatively light while the first two generations of squarks are heavy. We consider the general case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in (n \geq 2)jets + (m \geq 0)leptons + E^{miss}_T events depends rather strongly on the relation between LSP, second neutralino, gluino and squark masses and it decreases with the increase of LSP mass. We find that for relat…
In split supersymmetry, gauginos and Higgsinos are the only supersymmetric particles which are possibly accessible at foreseeable colliders. While the direct experimental searches, such as LEP and Tevatron experiments, gave robust lower bounds on the masses of these particles, the cosmic dark matter can give some upper bounds and thus have important implications for the searches at future colliders. In this work we scrutinize such dark matter constraints and show the allowed mass range for charginos and neutralinos (the mass eigenstates of gauginos and Higgsinos). We find that the lightest cha…
No-scale supersymmetry or gaugino mediation augmented with large negative Higgs soft masses at the input scale provides a simple solution to the supersymmetric flavor problem while giving rise to a neutralino LSP. However, to obtain a neutralino LSP it is often necessary to have tachyonic input Higgs soft masses that can give rise to charge-and-color-breaking (CCB) minima and unbounded-from-below (UFB) directions in the low energy theory. We investigate the vacuum structure in these theories to determine when such problematic features are present. When the standard electroweak vacuum is only m…
We present a model of supersymmetry breaking mediated through a small extra dimension. Standard model matter multiplets and a supersymmetry-breaking (or ``hidden'') sector are confined to opposite four-dimensional boundaries while gauge multiplets live in the bulk. The hidden sector does not contain a singlet and the dominant contribution to gaugino masses is via anomaly-mediated supersymmetry breaking. Scalar masses get contributions from both anomaly mediation and a tiny hard breaking of supersymmetry by operators on the hidden-sector boundary. These operators contribute to scalar masses at …
We demonstrate that natural supersymmetry is readily realized in the framework of SU(4)_c \times SU(2)_L \times SU(2)_R with non-universal 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 (Δ_{EW}) as well as at high scale (Δ_{HS}). It is possible to have both Δ_{EW} and Δ_{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 GeV-127 GeV range.…
We study gaugino-mediated supersymmetry breaking in a six-dimensional SO(10) orbifold GUT model where quarks and leptons are mixtures of brane and bulk fields. The couplings of bulk matter fields to the supersymmetry breaking brane field have to be suppressed in order to avoid large FCNCs. We derive bounds on the soft supersymmetry breaking parameters and calculate the superparticle mass spectrum. If the gravitino is the LSP, the stau_1 or the tau sneutrino turns out to be the NLSP, with characteristic signatures at future colliders and in cosmology.
We study dynamical gaugino condensation in superstring effective theories using the linear multiplet representation for the dilaton superfield. An interesting necessary condition for the dilaton to be stabilized, which was first derived in generic models of static gaugino condensation, is shown to hold for generic models of dynamical gaugino condensation. We also point out that it is stringy non-perturbative effects that stabilize the dilaton and allow dynamical supersymmetry breaking via the field-theoretical non-perturbative effect of gaugino condensation. As a typical example, a toy S-dual …
Grand unified theories can lead to non-universal boundary conditions for the gaugino masses at the unification scale. We consider the implications of such non-universal boundary conditions for the composition of the lightest neutralino as well as for the upper bound on its mass in the simplest supersymmetric grand unified theory based on the SU(5) gauge group. We derive sum rules for neutralino and chargino masses in different representations of SU(5) which lead to different non-universal boundary conditions for the gaugino masses at the unification scale. We also consider the phenomenological…
We consider supersymmetric theories where the standard-model quark and lepton fields are localized on a "3-brane" in extra dimensions, while the gauge and Higgs fields propagate in the bulk. If supersymmetry is broken on another 3-brane, supersymmetry breaking is communicated to gauge and Higgs fields by direct higher-dimension interactions, and to quark and lepton fields via standard-model loops. We show that this gives rise to a realistic and predictive model for supersymmetry breaking. The size of the extra dimensions is required to be of order 10-100 times larger than fundamental scale (e.…
From a theoretical point of view it is not hard to imagine gaugino masses being much lighter than scalar masses. The dominant contributions to gaugino masses are then their anomaly-mediated values. Given current lower bounds on gauginos, which are near the W-mass scale, considering a little hierarchy between weak-scale gauginos and much heavier scalars requires suspending normal intuition on finetuning and naturalness of the Higgs potential. Nevertheless, tantalizing perks come from the hypothesis: lessened flavor and CP violation problems, more compatibility with gauge coupling unification an…
We study gaugino condensation in the context of superstring effective theories using the linear multiplet formulation for the dilaton superfield. Including nonperturbative corrections to the Kähler potential for the dilaton may naturally achieve dilaton stabilization, with supersymmetry breaking and gaugino condensation; these three issues are interrelated in a very simple way. In a toy model with a single static condensate, a dilaton $vev$ is found within a phenomenologically interesting range. The effective theory differs significantly from condensate models studied previously in the chiral …
If supersymmetry is dynamically broken in a hidden sector, the gauginos typically have unacceptably small masses. This situation can be corrected if a non-Abelian gauge interaction becomes strong at a scale of order 1 TeV and induces dynamical gaugino masses. We discuss the typical signals of this scenario at present and future colliders.
We study phenomenological aspects of the soft supersymmetry breaking parameters in a model with the extended gauge mediation supersymmetry breaking. In this model gaugino masses can be non-universal and as its result physical CP-phases remain in the gaugino sector even after the R-transformation. These phases contribute to the electric dipole moment (EDM) of an electron and a neutron. We show that their experimental bounds can be satisfied even for the situation such that there exist the order one CP-phases and the masses of superpartners are of the order of 100 GeV.
We study the structure of soft breaking terms in the context of a gaugino condensation scenario. Assuming that the Supergravity Lagrangian is the correct quantum field theory limit, at some momentum scale $μ_{UV}$, of a more fundamental one, we demonstrate that the correct result is obtained simply by substituting, in the tree level Supergravity Lagrangian, $λλ$ (the gaugino condensate) by its vacuum expectation value $Λ^3$. In string inspired scenarios this implies, in particular, that the scalar masses are vanishing at the string tree-level and receive a contribution, at the one loop level, …
In gauge mediation models with multiple spurion fields breaking SUSY and the R-symmetry separately, we show that it is possible to generate gaugino masses at one loop if the R-charge arrangement satisfies a certain condition. The resulting gaugino masses are calculated and suppressed by some power of the messenger mass scale. We present two simple examples to demonstrate this possibility, and discuss possible phenomenology implications.
We consider different patterns of supersymmetry breaking gaugino masses, and implications of these patterns for the phenomenology of neutralinos and charginos in models of low energy supersymmetry. We outline a general procedure for obtaining approximate values for the neutralino masses relevant for our analysis, and describe the constraints on the gaugino mass parameters which follow from the present experimental limits on the mass of the lightest chargino. We evaluate an upper bound on the mass of the lightest neutralino that follows from the structure of the mass matrix in different models …
We introduce a new supersymmetric extension of the standard model in which the gauge sector contains complete N=2 supersymmetry multiplets. Supersymmetry breaking from the D-term vev of a hidden sector U(1) gauge field leads to Dirac soft supersymmetry breaking gaugino masses, and a new type of soft scalar trilinear couplings. The resulting squark and slepton masses are finite, calculable, positive and flavor universal. The Higgs soft mass squared is negative. The phenomenology of these theories differs significantly from the MSSM. We discuss a variety of possible origins for the soft operator…
I advocate the virtues of a very economical version of the minimal supersymmetric standard model which avoids cosmological problems often encountered in dynamical SUSY-breaking and solves the SUSY-CP problem. Imposing $m_Z=91$ GeV and $m_t \sim 175$ GeV implies that scalar masses are generally $100-200$ GeV. The gluino and photino are massless at tree level. At 1-loop, the gluino mass is predicted to be in the range $m_{\gluino}: 100 - 600$ MeV and the photino mass can be estimated to be $m_{\photino}: 100 - 1400$ MeV. New hadrons with mass $\sim 1 \frac{1}{2}$ GeV are predicted and described.…
I summarize recent devlopments in supersymmetry scenarios which leave some or all gauginos light. The emphasis is on experimental and phenomenological progress in the past year.
Supersymmetric models are typically taken to have $μ$ parameter and all soft supersymmetry breaking parameters at or near the weak scale. We point out that a small window of allowed values exists in which $μ$ and the electroweak gaugino masses are in the few GeV range. Such models naturally solve the supersymmetry $CP$ problem, can reduce the discrepancy in $R_b$, and suppress proton decay. In this window two neutralinos are in the few GeV range, two are roughly degenerate with the $Z^0$, and both charginos are roughly degenerate with the $W^{\pm}$ bosons. Such a signature cannot escape detect…
We consider the modifications to squark production in the presence of a naturally heavier Dirac gluino. First generation squark production is highly suppressed, providing an interesting but challenging signal find or rule out. No dedicated searches for supersymmetry with a Dirac gluino have been performed, however a reinterpretation of a "decoupled gluino" simplified model suggests the bounds on a common first and second generation squark mass is much smaller than in the MSSM: $\lsim 850$ GeV for a massless LSP, and no bound for an LSP heavier than about 300 GeV. We compare and contrast the sq…
We consider a gaugino-mediated supersymmetry breaking scenario where in addition to the gauginos the Higgs fields couple directly to the field that breaks supersymmetry. This yields non-vanishing trilinear scalar couplings in general, which can lead to large mixing in the stop sector providing a sufficiently large Higgs mass. Using the most recent release of FeynHiggs, we show the implications on the parameter space. Assuming a gravitino LSP, we find allowed points with a neutralino, sneutrino or stau NLSP. We test these points against the results of Run 1 of the LHC, considering in particular…
We consider supersymmetry breaking models in which the MSSM is extended to include an additional chiral adjoint field for each gauge group with which the the MSSM gauginos acquire Dirac masses. We investigate a framework in which the Standard Model gauge fields propagate in the bulk of a warped extra dimension while quarks and leptons are localized on the ultraviolet brane. The adjoint fields are localized on the infrared brane, where supersymmetry is broken in a hidden sector. This setup naturally suppresses potentially large flavor violating effects, while allowing perturbative gauge couplin…
Supersymmetry phenomenology is an important component of particle physics today. I provide a definition of supersymmetry phenomenology, outline the scope of its activity, and argue its legitimacy. This essay derives from a presentation given at the 2000 SLAC Summer Institute.
We analyze a direct-transmission model of dynamical SUSY breaking previously proposed. In the model the gravitino mass is naturally smaller than $1~\KEV$, which is required from the standard cosmology. We find that there are many distinguishable features from in other models: for example the so-called GUT relation among the gaugino masses does not hold even if we consider the GUT models. Furthermore, the gauginos are always lighter than the sfermions since the gaugino masses have extra suppression factors. We also discuss a collider signature ``$γγ+$ missing energy'' in the present model.
If supersymmetry is discovered at the LHC, the next question will be the determination of the underlying model. While this may be challenging or even intractable, a more optimistic question is whether we can understand the main contours of any particular paradigm of the mediation of supersymmetry breaking. The determination of superpartner masses through endpoint measurements of kinematic observables arising from cascade decays is a powerful diagnostic tool. In particular, the determination of the gaugino sector has the potential to discriminate between certain mediation schemes (not all schem…
This is a very pedagogical review of supersymmetry phenomenology, given at ICTP Summer School in 1999, aimed mostly at students who had never studied supersymmetry before. It starts with an analogy that the reason why supersymmetry is needed is similar to the reason why the positron exists. It introduces the construction of supersymmetric Lagrangians in a practical way. The low-energy constraints, renormalization-group analyses, collider phenomenology, and frameworks of mediating supersymmetry breaking are briefly discussed.
We argue that supersymmetry breaking by gaugino condensation in the strongly coupled heterotic string can be described by an analogue of Scherk-Schwarz compactification on the eleventh dimension in M-theory. The M-theory scale is identified with the gauge coupling unification mass, whereas the radius of the eleventh dimension $ρ$ is at an intermediate scale $ρ^{-1}\sim 10^{12}$ GeV. At the lowest order, supersymmetry is broken only in the gravitational and moduli sector at a scale $m_{3/2}\simρ^{-1}$, while it is mediated by gravitational interactions to the observable world. Computation of th…
We review the emergence and fate of goldstinos in different frameworks. First, we consider a super-Higgs mechanism when supersymmetry breaking is induced by neither an F-term nor a D-term but related to a more general stress energy-momentum tensor. This allows us to build a novel Lagrangian that describes the propagation of a spin-3/2 state in a fluid. Then we briefly review the ubiquitous pseudo-goldstinos when breaking supersymmetry in an extra dimension. We remind that the fermion (gravitino or gaugino) soft masses can be tuned to be of Dirac-type. Finally, we briefly connect the latter to …
Under a few mild assumptions, N=1 supersymmetry in four dimensions is shown to be spontaneously broken in a self-consistent Hartree-Fock approximation of BCS/NJL type to one-loop off-shell, in the gauge theory specified by the gauge kinetic function and the superpotential of adjoint chiral superfields, in particular, that possesses N=2 extended supersymmetry spontaneously broken to N=1 at tree level. The N=2 gauginos receive mixed Majorana-Dirac masses and are split. We derive an explicit form of the gap equation, showing the existence of a nontrivial solution.
We propose that a modified version of string-inspired supersymmetry breaking schemes in \cite{wit2} and \cite{ross} may make affine level one SU(5) and SO(10) string models with intermediate gauge symmetry breaking scale $M_{GUT}=10^{16}GeV$ possible; doublet-triplet problem can also be solved. In particular, we propose that some charged gauge background VEVs might be turned on when gaugino condensation happens in the hidden sector and would break gauge symmetry. One can dynamically determine gaugino condensation scale, local supersymmetry breaking scale and intermediate gauge symmetry breakin…
We investigate the formation of dynamical gaugino condensates and supersymmetry breaking in the compactifications of Horava-Witten theory with perturbative nonstandard embeddings. Specific models are considered where the underlying massless charged states of the condensing sector are determined by the spectra of $Z_2 \times Z_2 $ and $Z_4 $ orbifolds with nonstandard embeddings. We find among them viable examples where gaugino condensation is triggered on the wall with the weakest gauge coupling at $M_{GUT} $. In all these cases the magnitude of the condensate formed is below the energy scales…
Discovery of the Higgs boson and lack of discovery of superpartners in the first run at LHC are both predictions of split supersymmetry with thermal dark matter. We discuss what it would take to find gluinos at hadron supercolliders, including the LHC at 14 TeV center of mass energy, and future pp colliders at 100 TeV and 200 TeV. We generalize the discussion by re-expressing the search capacity in terms of gluino to lightest superpartner mass ratio, and apply results to other scenarios, such as gauge mediation and mirage mediation.
Generating gaugino masses at the leading order has typically been difficult in direct/semi-direct gauge mediated supersymmetry breaking models. The Komargodski-Shih theorem has established that local stability of the supersymmetry breaking vacuum implies a vanishing leading order gaugino mass in generic renormalizable O'Raifeartaigh models. We relax the condition of renormalizability and investigate the possibility to evade the KS no-go theorem using higher dimensional operators in the Kahler potential and the superpotential. We demonstrate that higher dimensional terms which are polynomial in…
The N=1 supergravity coupled to chiral and Yang-Mills superfields is regarded as the ultraviolet theory of the supersymmetric Standard Model. The gravitino acquires a mass from the hidden sector and participate in mediating supersymmetry breaking to the visible sector. We consider the quantum effects of the gravitino and evaluate its contribution to the gaugino masses at one loop level, which turns out to be irrespective of the SM gauge couplings. Due to the universality of gravitino, its contribution to the gaugino masses can significantly modify the gaugino mass relations of other supersymme…
We study supersymmetric QED in AdS4 with massless matter. At 1-loop the ultra-violet regulator of the theory generates a contribution to the gaugino mass that is naively inconsistent with unbroken supersymmetry. We show that this effect, known in flat space as anomaly mediated supersymmetry breaking, is required to cancel an infra-red contribution arising from the boundary conditions in AdS space, which necessarily break chiral symmetry. We also discuss an analogous UV/IR cancellation that is independent of supersymmetry.
