We explore the LHC phenomenology of an extension of warped higgsless models. The model is supersymmetric in the bulk and on the IR brane as introduced in [arXiv:0805.1379], corresponding to an emergence of a supersymmetric spectrum in the composite sector of the higgsless model. In particular, the lightest neutralino is rendered stable by an R parity and serves as a realistic cold dark matter candidate. The observation of missing energy signals at the LHC from LSP and NLSP production in association with third generation quarks is discussed based on simulations using WHIZARD.
We introduce a minimal supersymmetric extension of a higgsless model for electroweak symmetry breaking in a warped extra dimension. In contrast to the non supersymmetric version, our model naturally contains a candidate for cold dark matter. No KK-parity is required, because its stability is guaranteed by an R-parity. We discuss the regions in parameter that are compatible with the observed dark matter content of our universe and are allowed by electroweak precision measurements as well as direct searches.
We study tree level corrections to precision electroweak physics in the recently proposed Higgsless models in warped space. Such models inherit from their similarity with technicolor theories a large contribution to the oblique parameters, S in particular. We show that it is possible to suppress S using brane induced kinetic terms and unequal left-right bulk gauge couplings, paying the price of heavy KK modes. In the allowed region, they are eventually ineffective in restoring perturbative unitarity in W scattering above 2 TeV. Although it looks like a Higgsless models' bane, it has been recen…
We discuss the signatures of a representative Higgsless model with ideal fermion delocalization in vector-boson fusion processes, focusing on the gold- and silver-plated decay modes of the gauge bosons at the CERN-Large Hadron Collider. For this purpose, we have developed a fully-flexible parton-level Monte-Carlo program, which allows for the calculation of cross sections and kinematic distributions within experimentally feasible selection cuts at NLO-QCD accuracy. We find that Kaluza-Klein resonances give rise to very distinctive distributions of the decay leptons. Similar to the Standard Mod…
We have performed a detailed Monte Carlo exploration of the parameter space for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions. This model is based on the $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ gauge group in an AdS$_5$ bulk with arbitrary gauge kinetic terms on both the Planck and TeV branes. Constraints arising from precision electroweak measurements and collider data are found to be relatively easy to satisfy. We show, however, that the additional requirement of perturbative unitarity up to the cut-off, $\simeq 10$ TeV, in $W_L^+W_L^-$ elastic scattering in the …
We examine various possibilities for realistic 5D higgsless models and construct a full quark sector featuring next-to-minimal flavor violation (with an exact bulk SU(2) protecting the first two generations) satisfying electroweak and flavor constraints. The "new custodially protected representation" is used for the third generation to protect the light quarks from flavor violations induced due to the heavy top. A combination of flavor symmetries, and RS-GIM for the right-handed quarks suppresses flavor-changing neutral currents below experimental bounds, assuming CKM-type mixing on the UV bra…
We explore the LHC phenomenology of the dark matter candidate arising from the extension of warped Higgsless models. In particular, we consider a model of warped supersymmetry in the bulk and on the IR brane in which the lightest Neutralino is rendered stable by an R parity and serves as a realistic cold dark matter candidate. The production of the LSP and NLSP in association with third generation quarks is simulated using an implementation in O'Mega/Whizard.
The Higgsless model in warped extra dimension is reexamined. Dirichlet boundary conditions on the TeV brane are replaced with Robin boundary conditions which are parameterized by a mass parameter $M$. We calculate the Peskin-Takeuchi precision parameters $S$, $T$ and $U$ at tree level. We find that to satisfy the constraints on the precision parameters at $99 \%$ [$95 \%$] confidence level (CL) the first Kaluza-Klein excited $Z$ boson, $Z'$, should be heavier than 5 TeV [8 TeV]. The Magnitude of $M$, which is infinitely large in the original model, should be smaller than 200 GeV (70 GeV) for t…
We examine a warped Higgsless $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ model in 5--$d$ with IR(TeV)--brane kinetic terms. It is shown that adding a brane term for the $U(1)_{B-L}$ gauge field does not affect the scale ($\sim 2-3$ TeV) where perturbative unitarity in $W_L^+ W_L^- \to W_L^+ W_L^-$ is violated. This term could, however, enhance the agreement of the model with the precision electroweak data. In contrast, the inclusion of a kinetic term corresponding to the $SU(2)_D$ custodial symmetry of the theory delays the unitarity violation in $W_L^\pm$ scattering to energy scales of $\sim 6-…
We calculate the tree-level oblique corrections to electroweak precision observables generated in higgless models of electroweak symmetry breaking with a 5D SU(2)_L x SU(2)_R x U(1)_{B-L} gauge group on a warped background. In the absence of brane induced kinetic terms (and equal left and right gauge couplings) we find the S parameter to be ~1.15, while T,U~0, as in technicolor theories. Planck brane induced kinetic terms and unequal left-right couplings can lower S, however for sufficiently low values of S tree-level unitarity will be lost. A kinetic term localized on the TeV brane for SU(2)_…
We consider a five dimensional SU(2) gauge theory with fermions in the bulk and with additional SU(2) and U(1) kinetic terms on the branes. The electroweak breaking is obtained by boundary conditions. After deconstruction, fermions in the bulk are eliminated by using their equations of motion. In this way Standard Model fermion mass terms and direct couplings to the internal gauge bosons of the moose are generated. The presence of these new couplings gives a new contribution to the epsilon_3 parameter in addition to the gauge boson term. This allows the possibility of a cancellation between th…
We study a theory of electroweak symmetry breaking without a Higgs boson, recently suggested by Csaki et al. The theory is formulated in 5D warped space with the gauge bosons and matter fields propagating in the bulk. In the 4D dual picture, the theory appears as the standard model without a Higgs field, but with an extra gauge group G which becomes strong at the TeV scale. The strong dynamics of G breaks the electroweak symmetry, giving the masses for the W and Z bosons and the quarks and leptons. We study corrections in 5D which are logarithmically enhanced by the large mass ratio between th…
We examine the phenomenology of a warped 5-dimensional model based on SU(2)$_L \times$ SU(2)$_R \times$ U(1)$_{B-L}$ model which implements electroweak symmetry breaking through boundary conditions, without the presence of a Higgs boson. We use precision electroweak data to constrain the general parameter space of this model. Our analysis includes independent $L$ and $R$ gauge couplings, radiatively induced UV boundary gauge kinetic terms, and all higher order corrections from the curvature of the 5-d space. We show that this setup can be brought into good agreement with the precision electrow…
It is possible to construct models based on warped extra dimensions in which electroweak symmetry breaking takes place without the introduction of any Higgs fields. This breaking can occur through the judiciuous choice of boundary conditions applied to gauge fields living in the bulk. One then finds that the fifth components of these bulk fields act as the Goldstone bosons, even for the would-be zero modes of the Kaluza-Klein tower. In this talk I will discuss the phenomenology of such scenarios, in particular, the problems associated with the construction of realistic models due to the simult…
In warped models that solve the hierarchy problem, there is generally no dynamical relation between the size of the fifth dimension and the scale of electroweak symmetry breaking (EWSB). The establishment of such a relation, without fine-tuning, requires that Casimir contributions to the radion potential not exceed the energy density associated with EWSB. Here, we examine the use of supersymmetry for controlling the Casimir energy density and making quantum contributions calculable. We compute the effects of supersymmetry breaking at the UV and IR boundaries of warped backgrounds, in the prese…
We examine the soft supersymmetry breaking parameters in supersymmetric theories on a slice of AdS_5 which generate the hierarchical Yukawa couplings by dynamically localizing the bulk matter fields in extra dimension. Such models can be regarded as the AdS dual of the recently studied 4-dimensional models which contain a supersymmetric CFT to generate the hierarchical Yukawa couplings. In such models, if supersymmetry breaking is mediated by the bulk radion superfield and/or some brane chiral superfields, potentially dangerous flavor-violating soft parameters can be naturally suppressed, ther…
We compute radiative correction to the lightest neutral Higgs mass ($m_h$) induced by the Kaluza-Klein (KK) towers of fermions and sfermions in a minimal supersymmetric scenario embeded in a 5-dimensional warped space. The Higgs is confined to the TeV brane. The KK spectra of matter supermultiplets is tied to the explanation of the fermion mass hierarchy problem. We demonstrate that for a reasonable choice of extra-dimensional parameters, the KK-induced radiative correction can enhance the upper limit on $m_h$ by as much as 100 GeV beyond the 4d limit of 135 GeV.
We investigate and compare additional CP-even, CP-odd and charged scalar states appearing in two popular Beyond the Standard Model scenarios. We focus on the simplest possible Higgs sector within warped extra-dimensions and supersymmetry, with the aim to differentiate between them. In each case, we analyze the couplings of the new Higgs states, looking for distinguishing signatures. We show that the couplings of the Standard Model gauge bosons to the first Kaluza-Klein Higgs states of the extra-dimensional setup (CP-even, CP-odd and charged) are very similar to those of the heavy Higgs states …
We present a 5D gauge theory in warped space based on a bulk SU(2)_L x SU(2)_R x U(1)_(B-L) gauge group where the gauge symmetry is broken by boundary conditions. The symmetry breaking pattern and the mass spectrum resembles that in the standard model (SM). To leading order in the warp factor the rho parameter and the coupling of the Z (or equivalently the S-parameter) are as in the SM, while corrections are expected at the level of a percent. From the AdS/CFT point of view the model presented here can be viewed as the AdS dual of a (walking) technicolor-like theory, in the sense that it is th…
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 …
Supersymmetry breaking together by constant boundary superpotentials and by the O'Raifeartaigh model is studied in a warped space model. It is shown that the contribution of constant boundary superpotentials enables the moduli of chiral supermultiplets to be stabilized and that the vacuum at the stationary point has zero cosmological constant in a wide region of parameters.
We study a supersymmetric deconstructed gauge theory in which a warp factor emerges dynamically, driven by Fayet-Iliopoulos terms. The model is peculiar in that it possesses a global supersymmetry that remains unbroken despite nonvanishing D-term vacuum expectation values. Inclusion of gravity and/or additional messenger fields leads to the collective breaking of supersymmetry and to an unusual phenomenology.
In this thesis we have explored some of the phenomenological aspects of warped/flat extra dimensional theories and their interface with supersymmetry. We study the numerical impact of compactified warped extra dimension on the processes gg -> h and h -> γγ, which are of paramount importance in the context of Higgs search at the LHC. We compute radiative correction to the lightest neutral Higgs mass induced by the Kaluza-Klein (KK) towers of fermions and sfermions in a supersymmetric warped extra dimension model. Next we make a more formal renormalization group study of a supersymmetric model e…
Supersymmetry breaking by constant (field independent) superpotentials localized at boundaries is studied in a supersymmetric warped space model. We calculate the Kaluza-Klein mass spectrum of the hypermultiplet. We take into account of the radion and the compensator supermultiplets, as well as the bulk mass $c$ for the hypermultiplet. The mass splitting is similar to that of the Scherk-Schwarz supersymmetry breaking (in flat space) for large $|c|$, and has an interesting dependence on the bulk mass parameter $c$. We show that the radius is stabilized by the presence of the constant boundary s…
Explicit supersymmetry breaking is studied in higher dimensional theories by having boundaries respect only a subgroup of the bulk symmetry. If the boundary symmetry is the maximal subgroup allowed by the boundary conditions imposed on the fields, then the symmetry can be consistently gauged; otherwise gauging leads to an inconsistent theory. In a warped fifth dimension, an explicit breaking of all bulk supersymmetries by the boundaries is found to be inconsistent with gauging; unlike the case of flat 5D, complete supersymmetry breaking by boundary conditions is not consistent with supergravit…
We study the five-dimensional (5D) supergravity compactified on an orbifold S^1/Z_2, where the U(1)_R symmetry is gauged by the graviphoton with Z_2-even coupling. In contrast to the case of gauging with Z_2-odd coupling, this class of models has Majorana-type masses and allows the Scherk-Schwarz (SS) twist even in the warped spacetime. Starting from the off-shell formulation, we show that the supersymmetry is always broken in an orbifold slice of AdS_5, irrespective of the value of the SS twist parameter. We analyze the spectra of gaugino and gravitino in such background, and find the SS twis…
Supersymmetry breaking and radius stabilization by constant superpotentials localized at boundaries is studied in a supersymmetric warped space model where a hypermultiplet, a compensator and a radion multiplet are taken into account. Soft mass induced by the anomaly mediation can be of the order of 100GeV and can be dominant compared to that mediated by bulk fields. A lighter physical mode composed of the radion and the moduli can have mass of the order of a TeV and the gravitino mass can be of the order of 10^7 GeV. The radius is stabilized by the presence of the constant boundary superpoten…
We consider supersymmetric theories with a warped extra dimension where supersymmetry is broken by boundary conditions that preserve an R-symmetry. It is shown that this supersymmetry breaking mechanism naturally invokes the Stuckelberg formalism for the gravitino in order to give a four-dimensional theory with a smooth massless limit.
We study deconstructed gauge theories in which a warp factor emerges dynamically and naturally. We present nonsupersymmetric models in which the potential for the link fields has translational invariance, broken only by boundary effects that trigger an exponential profile of vacuum expectation values. The spectrum of physical states deviates exponentially from that of the continuum for large masses; we discuss the effects of such exponential towers on gauge coupling unification. We also present a supersymmetric example in which a warp factor is driven by Fayet-Iliopoulos terms. The model is pe…
We study the breaking of supersymmetry in five-dimensional (5d) warped spaces, using the Randall-Sundrum model as a prototype. In particular, we present a supersymmetry-breaking mechanism which has a geometrical origin, and consists of imposing different boundary conditions between the fermions and bosons living in the 5d bulk. The scale of supersymmetry breaking is exponentially small due to the warp factor of the AdS metric. We apply this mechanism to a supersymmetric standard model where supersymmetry breaking is transmitted through the AdS bulk to matter fields confined on the Planck-brane…
We study the existence of metastable vacua in cascades based on fractional brane configurations at non-isolated singularities preserving N = 1 supersymmetry. We find that in a large class of models the extra moduli typically generated along such cascades may be stabilized by utilizing special monopole points found recently. We illustrate this in detail for cascades based on the SPP singularity. The supergravity interpretation of these constructions in terms of warped throats with supersymmetry breaking localized near their tips as well as applications to string compactification is discussed. O…
We explore the possibility of solving the hierarchy problem by combining the paradigms of supersymmetry and compositeness. Both paradigms are under pressure from the results of the Large Hadron Collider (LHC), and combining them allows both a higher confinement scale -- due to effective supersymmetry in the low energy theory -- and heavier superpartners -- due to the composite nature of the Higgs boson -- without sacrificing naturalness. The supersymmetric Randall-Sundrum model provides a concrete example where calculations are possible, and we pursue a realistic model in this context. With a …
Supersymmetric unification in warped space provides new possibilities for model building. I argue that the picture of warped supersymmetric unification arises naturally through the AdS/CFT correspondence from the assumption that supersymmetry is dynamically broken at a scale about (10 - 100) TeV, and present several fully realistic theories in this framework. In the minimal model, the bulk SU(5) gauge group is broken at the Planck brane by boundary conditions, while supersymmetry is broken at the TeV brane. The theory preserves the successes of conventional supersymmetric unification, and yet …
In warped supersymmetric grand unification, XY gauge particles appear near the TeV scale along with Kaluza-Klein towers of the standard model gauge fields. In spite of this exotic low-energy physics, MSSM gauge coupling unification is preserved and proton decay is naturally suppressed. In this paper we study in detail the low-lying mass spectrum of superparticles and GUT particles in this theory, taking supersymmetry breaking to be localized to the TeV brane. The masses of the MSSM particles, Kaluza-Klein modes, and XY states are all determined by two parameters, one which fixes the strength o…
We study a gauge theory in a 5D warped space via the dimensional deconstruction that a higher dimensional gauge theory is constructed from a moose of 4D gauge groups. By the AdS/CFT correspondence, a 5D warped gauge theory is dual to a 4D conformal field theory (CFT) with a global symmetry. As far as physics of the gauge theory, we obtain the one-to-one correspondence between each component of a moose of gauge groups and that of a CFT. We formulate a supersymmetric extension of deconstruction and explore the framework of natural supersymmetry in a 5D warped space -- the supersymmetric Randall-…
We study the phenomenon of accidental or "emergent" supersymmetry within gauge theory and connect it to the scenarios of Split Supersymmetry and Higgs compositeness. Combining these elements leads to a significant refinement and extension of the proposal of Partial Supersymmetry, in which supersymmetry is broken at very high energies but with a remnant surviving to the weak scale. The Hierarchy Problem is then solved by a non-trivial partnership between supersymmetry and compositeness, giving a promising approach for reconciling Higgs naturalness with the wealth of precision experimental data.…
We propose a simple model of extra-dimensional radius stabilization in a supersymmetric Randall-Sundrum model. In our model, we introduce only a bulk hypermultiplet and source terms (tadpole terms) on each boundary branes. With appropriate choice of model parameters, we find that the radius can be stabilized by supersymmetric vacuum conditions. Since the radion mass can be much larger than the gravitino mass and even the original supersymmetry breaking scale, radius stability is ensured even in the presence of supersymmetry breaking. We find a parameter region in which unwanted scalar masses i…
Warped compactifications with branes provide a new approach to the hierarchy problem and generate a diversity of four-dimensional thresholds. We investigate the relationships between these scales, which fall into two classes. Geometrical scales, such as thresholds for Kaluza-Klein, excited string, and black hole production, are generically determined soley by the spacetime geometry. Dynamical scales, notably the scale of supersymmetry breaking and moduli masses, depend on other details of the model. We illustrate these relationships in a class of solutions of type IIB string theory with imagin…
In the scenario where only superpartners were produced at the Large Hadron Collider, how one could determine whether the supersymmetric model pointed out is 4-dimensional or higher-dimensional ? We propose and develop a series of tests for discriminating between a pure supersymmetry (SUSY) and a SUSY realized within the well-motivated warped geometry a la Randall-Sundrum (RS). Two of these tests make use of some different patterns arising in the squark/slepton mass spectrum. The other distinctive RS SUSY feature is the possibly larger (even dominant) Higgs boson decay branching ratios into sle…
We present an N=1 superfield formulation of supersymmetric gauge theories with a compact extra dimension. The formulation incorporates the radion superfield and allows to write supersymmetric theories on warped gravitational backgrounds. We apply it to study the breaking of supersymmetry by the F-term of the radion, and show that, for flat extra dimensions, this leads to the same mass spectrum as in Scherk-Schwarz models of supersymmetry breaking. We also consider scenarios where supersymmetry is broken on a boundary of a warped extra dimension and compare them with anomaly mediated models.
We discuss ideal delocalization of fermions in a bulk SU(2) x SU(2) x U(1) Higgsless model with a flat or warped extra dimension. So as to make an extra dimensional interpretation possible, both the weak and hypercharge properties of the fermions are delocalized, with the U(1)_Y current of left-handed fermions being correlated with the SU(2)_W current. We find that (to subleading order) ideal fermion delocalization yields vanishing precision electroweak corrections in this continuum model, as found in corresponding theory space models based on deconstruction. In addition to explicit calculatio…
We develop the formalism of "General gauge mediation" for five dimensional theories in a slice of AdS space. A set of current correlators encodes the effect of a supersymmetry breaking hidden sector localised on the IR brane. These current correlators provide a tree-level gaugino mass and loop-level sfermion masses on the UV brane. We also use this formalism to calculate the Casimir energy and masses for bulk hyperscalars. To illustrate this general construction we consider a perturbative hidden sector of generalised messengers coupled to a spurion. For models with large warping, we find that …
We present a new supersymmetric extension of the standard model. The model is constructed in warped space, with a unified bulk symmetry broken by boundary conditions on both the Planck and TeV branes. In the supersymmetric limit, the massless spectrum contains exotic colored particles along with the particle content of the minimal supersymmetric standard model (MSSM). Nevertheless, the model still reproduces the MSSM prediction for gauge coupling unification and does not suffer from a proton decay problem. The exotic states acquire masses from supersymmetry breaking, making the model completel…
We point out that supersymmetric warped geometry can provide a solution to the SUSY flavor problem, while generating hierarchical Yukawa couplings. In supersymmetric theories in a slice of AdS_5 with the Kaluza-Klein scale M_KK much higher than the weak scale, if all visible fields originate from 5D bulk fields and supersymmetry breaking is mediated by the bulk radion superfield and/or some brane chiral superfields, potentially dangerous soft scalar masses and trilinear $A$ parameters at M_KK can be naturally suppressed compared to the gaugino masses by small warp factor. We present simple mod…
We study gauged five-dimensional supergravity on the interval [0,πR]. We find a set of boundary conditions with respect to which the theory is locally supersymmetric. For theories with detuned brane tensions (Λ_4<0), we show that these boundary conditions can be used to spontaneously break global supersymmetry. For the original, tuned Randall-Sundrum scenario (Λ_4=0), we prove that the locally supersymmetric boundary conditions are also globally supersymmetric. We lift the theory from [0,πR] to S^1 and R, with arbitrary twists for the fermions, and cast these results in the language of the Sch…
It is generally believed that weak scale supersymmetry implies weak scale supergravity, in the sense that the masses of the gravitino and gravitationally coupled moduli have masses below 100 TeV. This paper presents a realistic framework for supersymmetry breaking in the hidden sector in which the masses of the gravitino and gravitational moduli can be much larger. This cleanly eliminates the cosmological problems of hidden sector models. Supersymmetry breaking is communicated to the visible sector by anomaly-mediated supersymmetry breaking. The framework is compatible with perturbative gauge …
The suppression of flavor and CP violation in supersymmetric theories may be due to the mechanism responsible for the structure of the Yukawa couplings. We study model independently the compatibility between low energy flavor and CP constraints and observability of superparticles at the LHC, assuming a generic correlation between the Yukawa couplings and the supersymmetry breaking parameters. We find that the superpotential operators that generate scalar trilinear interactions are generically problematic. We discuss several ways in which this tension is naturally avoided. In particular, we foc…
We study a 5d gravity theory with a warped metric and show that two N = 2 supersymmetric quantum-mechanical systems are hidden in the 4d spectrum. The supersymmetry can be regarded as a remnant of higher-dimensional general coordinate invariance and turns out to become a powerful tool to determine the physical 4d spectrum and the allowed boundary conditions. Possible extensions of the N = 2 supersymmetry are briefly discussed.
We present four-dimensional gauge theories that describe physics on five-dimensional curved (warped) backgrounds, which includes bulk fields with various spins (vectors, spinors, and scalars). Field theory on the AdS$_5$ geometry is examined as a simple example of our formulation. Various properties of bulk fields on this background, e.g., the mass spectrum and field localization behavior, can be achieved within a fully four-dimensional framework. Moreover, that gives a localization mechanism for massless vector fields. We also consider supersymmetric cases, and show in particular that the con…
We construct supersymmetric theories in which the correct scale for electroweak symmetry breaking is obtained without significant fine-tuning. We calculate the fine-tuning parameter for these theories to be at the 20% level, which is significantly better than in conventional supersymmetry breaking scenarios. Supersymmetry breaking occurs at a low scale of order 100 TeV, and is transmitted to the supersymmetric standard-model sector through standard-model gauge interactions. The Higgs sector contains two Higgs doublets and a singlet field, with a superpotential that takes the most general form …
We present a model of dark matter in a warped extra dimension in which the dark sector mass scales are naturally generated without supersymmetry. The dark force, responsible for dark matter annihilating predominantly into leptons, is mediated by dark photons that naturally obtain a mass in the GeV range via a dilaton coupling. As well as solving the gauge hierarchy problem, our model predicts dark matter in the TeV range, including naturally tiny mass splittings between pseudo-Dirac states. By the AdS/CFT correspondence both the dark photon and dark matter are interpreted as composite states o…
We discuss the motivation and the phenomenology of models with either flat or warped extra dimensions. We describe the typical mass spectrum and discovery signatures of such models at the LHC. We also review several proposed methods for discriminating the usual low-energy supersymmetry from a model with flat (universal) extra dimensions. (For the official website of the book, see http://cambridge.org/us/catalogue/catalogue.asp?isbn=9780521763684 .)
We investigate the possibility that supersymmetry is not a fundamental symmetry of nature, but emerges as an accidental approximate global symmetry at low energies. This can occur if the visible sector is non-supersymmetric at high scales, but flows toward a strongly-coupled superconformal fixed point at low energies; or, alternatively, if the visible sector is localized near the infrared brane of a warped higher-dimensional spacetime with supersymmetry broken only on the UV brane. These two scenarios are related by the AdS/CFT correspondence. In order for supersymmetry to solve the hierarchy …
Many extensions of the Standard Model have to face the problem of new unsuppressed baryon-number violating interactions. In supersymmetry, the simplest way to solve this problem is to assume R-parity conservation. As a result, the lightest supersymmetric particle becomes stable and a well-motivated dark matter candidate. In this paper, we show that solving the problem of baryon number violation in non supersymmetric grand unified theories (GUT's) in warped higher-dimensional spacetime can lead to a stable Kaluza-Klein particle. This exotic particle has gauge quantum numbers of a right-handed n…
We propose a scenario of gravity mediated supersymmetry breaking (gravity mediation) in a supersymmetric Randall-Sundrum model. In our setup, both of the visible sector and the hidden sector co-exist on the infrared (IR) brane. We introduce the Polonyi model as a simple hidden sector. Due to the warped metric, the effective cutoff scale on the IR brane is ``warped down'', so that the gravity mediation occurs at a low scale. As a result, the gravitino is naturally the lightest superpartner (LSP) and contact interactions between the hidden and the visible sector fields become stronger. We addres…
We construct a realistic theory of grand unification in AdS_5 truncated by branes, in which the unified gauge symmetry is broken by boundary conditions and the electroweak scale is generated by the AdS warp factor. We show that the theory preserves the successful gauge coupling unification of the 4D MSSM at leading-logarithmic level. Kaluza-Klein (KK) towers, including those of XY gauge and colored Higgs multiplets, appear at the TeV scale, while the extra dimension provides natural mechanisms for doublet-triplet splitting and proton decay suppression. In one possible scenario supersymmetry is…
Gravity mediation supersymmetry breaking become comparable to gauge mediated supersymmetry breaking contributions when messenger masses are close to the GUT scale. By suitably tuning the gravity contributions one can then modify the soft supersymmetry breaking sector to generate a large stop mixing parameter and a light higgs mass of 125 GeV. In this kind of hybrid models, however the nice features of gauge mediation like flavour conservation etc, are lost. To preserve the nice features, gravitational contributions should become important for lighter messenger masses and should be important on…
We investigate, in the general framework of KKLT, the mediation of supersymmetry breaking by fields propagating in the strongly warped region of the compactification manifold ('throat fields'). Such fields can couple both to the supersymmetry breaking sector at the IR end of the throat and to the visible sector at the UV end. We model the supersymmetry breaking sector by a chiral superfield which develops an F-term vacuum expectation value. It turns out that the mediation effect of vector multiplets propagating in the throat can compete with modulus-anomaly mediation. Moreover, such vector fie…
