Warped scenarios offer an appealing solution to the hierarchy problem. We consider a non-trivial deformation of the basic Randall-Sundrum framework that has a KK-parity symmetry. This leads to a stable particle beyond the Standard Model, that is generically expected to be the first KK-parity odd excitation of the radion field. We consider the viability of the KK-radion as a DM candidate in the context of thermal and non-thermal production in the early universe. In the thermal case, the KK-radion can account for the observed DM density when the radion decay constant is in the natural multi-TeV range. We also explore the effects of coannihilations with the first KK excitation of the RH top, as well as the effects of radion-Higgs mixing, which imply mixing between the KK-radion and a KK-Higgs (both being KK-parity odd). The non-thermal scenario, with a high radion decay constant, can also lead to a viable scenario provided the reheat temperature and the radion decay constant take appropriate values, although the reheat temperature should not be much higher than the TeV scale. Direct detection is found to be feasible if the DM has a small (KK-parity odd) Higgs admixture. Indirect detection via a photon signal from the galactic center is an interesting possibility, while the positron and neutrino fluxes from KK-radion annihilations are expected to be rather small. Colliders can probe characteristic aspects of the DM sector of warped scenarios with KK-parity, such as the degeneracy between the radion and the KK-radion (DM) modes.
In the usual 5-dimensional Randall-Sundrum scenario with warped geometry of the extra compact dimension, the Goldberger-Wise mechanism for stabilisation of the radius of compactification can lead to a scalar field called the radion. The radion can have implications in TeV-scale physics, which can be especially noticeable if its vacuum expectation value (vev) is not far above a TeV. However a large mass of the first graviton excitation, which seems to be suggested by recent search limit, tends to make the radion vev, far too large in the minimal model. We show that this is not the case if a Gau…
We show that the radion in a warped geometry bounded by two branes can have a potential suitable for inflation. Our construction is based upon a solution known in string theory as the linear dilaton, in which the back-reaction from a bulk scalar Φis exactly accounted for. The radion, stabilized by Φ, is much heavier than the TeV scale and its couplings to the standard model are much more suppressed than in the usual Randall-Sundrum solution. We present a new formalism for obtaining approximate time-dependent solutions, based on perturbing the exact solution to the coupled Einstein and scalar f…
We study implications of generalized non-zero Dirichlet boundary condition along with the ordinary Neumann one on a bulk scalar in the Randall-Sundrum warped compactification. First we show profiles of vacuum expectation value of the scalar under the general boundary conditions. We also investigate Goldberger-Wise mechanism in several setups with the general boundary conditions of the bulk scalar field and find that the mechanism can work under non-zero Dirichlet boundary conditions with appropriate vacuum expectation values. Especially, we show that $SU(2)_R$ triplet Higgs in the bulk left-ri…
We analyze the flavor violation in warped extra dimension due to radion mediation. We show that ΔS=2 and ΔB=2 flavor violating processes impose stringent constraints on radion mass, m_ϕand the scale Λ_ϕ. In particular, for Λ_ϕ~ O(1) TeV, B_d^0-\bar{B}^0_d implies that m_ϕ~ 65 GeV. We also study radion contributions to lepton flavor violating processes: τ-> (e,μ) ϕ, τ-> eμ^+μ^- and B -> l_i l_j. We show that BR(B_s -> μ^+ μ^-) can be of order 10^{-8}, which is reachable at the LHCb. The radion search at LHC, through the flavor violation decays into τμor top-charm quarks, is also considered.
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 study constraints on the radion mass and couplings in the Randall-Sundrum model from the recent LHC data on the Standard Model (SM) Higgs boson searches. When the radion is heavy enough so that it can decay into a pair of on-shell Z-bosons, we find that the ZZ channel gives a stringent constraint. For example, if the radion mass m_ϕis 200 GeV, the scale Λ_ϕwhich characterizes the interactions of the radion with the SM fields must be larger than 5 TeV. Even for m_ϕ=1 TeV, we find that the lower bound on Λ_ϕis 2 TeV.
Theories beyond the Standard Model often contain mass scales hierarchically different from the electroweak scale and the Planck scale. It has been shown that such hierarchical mass scales can be realized as typical energy scales of multiple 3-branes in a 5D warped spacetime. We present a mechanism for stabilizing the intervals between the multiple 3-branes in the warped extra dimension, by introducing a single 5D scalar field with brane-localized potentials. We discuss the radion stabilization by solving the Einstein equation and the scalar field equation of motion so that a backreaction effec…
We study radion phenomenology in the context of flavor shining in warped extra dimension models. In this unique setup, originally proposed by Rattazzi and Zaffaroni, solutions to the gauge hierarchy problem and the new physics flavor problem are unified. A special role is played by the vacuum energy on the branes, that naturally allows for flavon stabilization and parametrically raises the radion mass. We note that the radion mass squared is suppressed only by the log of the weak-Planck hierarchy, and it is in the favored range of the standard model Higgs. We emphasize that the radion to di-ph…
The radion scalar field might be the lightest new particle predicted by extra-dimensional extensions of the Standard Model, thus possibly leading to the first signatures of new physics at the LHC. We perform a study of its production in association with a $Z$ boson in the custodially protected warped model with a brane-localised Higgs boson addressing the gauge hierarchy problem, with Higgs-radion mixing effects included. While the considered radion production at the LHC would constrain some parts of the parameter space, it is only the ILC program that will be able to cover a significant part …
We derive the Lagrangian and Feynman rules up to bilinear scalar fields for the mixed Higgs-radion eigenstates interacting with Standard Model particles confined to a 3-brane in Randall-Sundrum warped geometry. We use the results to compute precision electroweak observables and compare theory predictions with experiment. We characterize the interesting regions of parameter space that simultaneously enable a very heavy Higgs mass and a very heavy radion mass, both masses being well above the putative Higgs boson mass limit in the Standard Model derived from the constraints of precision electrow…
The radion scalar field might be the lightest new particle predicted by extra-dimensional extensions of the Standard Model. It could thus lead to the first signatures of new physics at the LHC collider. We perform a complete study of the radion production in association with the Z gauge boson in the custodially protected warped model with a brane-localised Higgs boson addressing the gauge hierarchy problem. Radion-Higgs mixing effects are present. Such a radion production receives possibly resonant contributions from the Kaluza-Klein excitations of the Z boson as well as the extra neutral gaug…
We study a generalization of the Randall-Sundrum mechanism for generating the weak/Planck hierarchy, which uses two rather than one warped extra dimension, and which requires no negative tension branes. A 4-brane with one exponentially large compact dimension plays the role of the Planck brane. We investigate the dynamical stability with respect to graviton, graviphoton and radion modes. The radion is shown to have a tachyonic instability for certain models of the 4-brane stress-energy, while it is stable in others, and massless in a special case. If stable, its mass is in the milli-eV range, …
We consider the Higgs-radion mixing in the context of warped space extra dimensional models with custodial symmetry and investigate the prospects of detecting the mixed radion. Custodial symmetries allow the Kaluza-Klein excitations to be lighter, and protect Zbb to be in agreement with experimental constraints. We perform a complementary study of discovery reaches of the Higgs-radion mixed state at the 13 and 14 TeV LHC and at the 500 and 1000 GeV ILC. We carry out a comprehensive analysis of the most significant production and decay modes of the mixed radion in the 80 GeV - 1 TeV mass range,…
We investigate the phenomenology of the Randall-Sundrum radion in realistic models of electroweak symmetry breaking with bulk gauge and fermion fields, since the radion may turn out to be the lightest particle in such models. We calculate the coupling of the radion in such scenarios to bulk fermion and gauge modes. Special attention needs to be devoted to the coupling to massless gauge fields (photon, gluon), since it is well known that loop effects may be important for these fields. We also present a detailed explanation of these couplings from the CFT interpretation. We then use these coupli…
A warped space model with a constant boundary superpotential has been an efficient model both to break supersymmetry and to stabilize the radius, when hypermultiplet, compensator and radion multiplet are taken into account. In such a model of the radius stabilization, the radion and moduli masses, the gravitino mass and the induced soft masses are studied. We find that a lighter physical mode composed of the radion and the moduli can have mass of the order of a TeV and that the gravitino mass can be of the order of 10$^7$ GeV. It is also shown that soft mass induced by the anomaly mediation ca…
We consider the Kaluza-Klein (KK) graviton and its decays in the presence of the light radion, the modulus of extra dimension, appearing naturally light due to classical scale invariance in warped gravity. Due to the presence of a sizable wavefunction overlap in the extra dimension between the KK graviton and the radion, the KK graviton can decay largely into a pair of radions, each of which decays into a pair of collimated photons or photon-jets. Focusing on the setup where the KK graviton has suppressed couplings to the Higgs boson and fermions, we discuss the bounds on the light radion in t…
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…
In the context of higher dimensional braneworld scenario, the stabilisation of extra dimensional modulus is an essential requirement for resolving the gauge hierarchy problem in the context of Standard Model of elementary particle Physics. For Randall-Sundrum (RS) warped extra dimensional model, Goldberger and Wise (GW) proposed a much useful mechanism to achieve this using a scalar field in the bulk spacetime ignoring the effects of backreaction of the scalar field on the background metric. In this article we examine the influence of the backreaction of the stabilising field on the stabilisat…
A recently proposed warped top-condensation model generally predicts a light radion ϕ, with a mass of a few GeV or less, whose interactions are suppressed by a scale of order 100 TeV. In this talk, we present existing constraints and potential signals from the process b \to s ϕ, in the context of such a model. Astrophysical bounds, applicable to very light radions, are also briefly discussed.
Precision data generally require the threshold for physics beyond the Standard Model to be at the deca-TeV (10 TeV) scale or higher. This raises the question of whether there are interesting deca-TeV models for which the LHC may find direct clues. A possible scenario for such physics is a 5D warped model of fermion masses and mixing, with Kaluza-Klein masses m_KK ~ 10 TeV, allowing it to avoid tension with stringent constraints, especially from flavor data. Discovery of a Standard-Model-like Higgs boson, for which there are some hints at ~125 GeV at the LHC, would also require the KK masses to…
We present a possible explanation for the smallness of the observed cosmological constant using a variant of the Randall-Sundrum(RS)- Goldberger-Wise paradigm for a warped extra dimension. In contrast to RS, we imagine that we are living on the positive tension Planck brane, or on a zero-tension TeV brane. In our model there are two solutions for the scalar field in the bulk and the corresponding brane separations, one of which is tuned to have zero cosmological constant. We show that in the other solution, which is a false vacuum state, the 4-D cosmological constant can be naturally small, du…
We examine the cosmology and hierarchy of scales in models with branes immersed in a five-dimensional curved spacetime subject to radion stabilization. When the radion field is time-independent and the inter-brane spacing is stabilized, the universe can naturally find itself in the radiation-dominated epoch. This feature is independent of the form of the stabilizing potential. We recover the standard Friedmann equations without assuming a specific form for the bulk energy-momentum tensor. In the models considered, if the observable brane has positive tension, a solution to the hierarchy proble…
We study radion phenomenology in an warped extra-dimension scenario with Standard Model fields in the bulk, with and without an additional fourth family of fermions. The radion couplings with the fermions will be generically misaligned with respect to the Standard Model fermion mass matrices, therefore producing some amount of flavor violating couplings and potentially influencing production and decay rates of the radion. Simple analytic expressions for the radion-fermion couplings are obtained with three or four families. We also update and analyze the current experimental limits on radion co…
We point out that the light radion phi in a recently proposed Warped Top-Condensation Model, can provide distinct signatures in b -> s phi, where the on-shell phi can decay with displaced vertices. We find that some of the parameter space of these models is constrained by B-meson and astrophysical data. Future B-decay measurements can lead to the discovery of the WTCM.
In the context of warped scenarios in which Standard Model (SM) fields are allowed to propagate in the bulk, we revisit the possible mixing between the IR localized Higgs field and the Radion graviscalar. The phenomenology of the resulting mostly-Higgs field does not suffer important deviations with respect to the case in which all the SM is localized in the IR brane (original Higgs-Radion mixing scenario). On the contrary, the phenomenology of the mostly-Radion field can present important differences with respect to the original scenario. At the LHC, the most striking effect is now the possib…
A warped extra dimension model predicts an extra scalar particle beyond the Standard Model which is called a radion. Although interactions of the radion are similar to those of the Higgs boson in the Standard Model, a relatively light radion ($\lesssim 100 {\rm GeV}$) is not severely constrained from the Higgs search experiments at the LHC. In this paper we study discovery potential of the radion at a photon collider as an option of ILC. Owing to the trace anomaly of the energy-momentum tensor, both a production of radion in $γγ$ collision and its decay to gluon pair are enhanced sizably. We f…
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…
We consider a 5D warped scenario with a KK-parity symmetry, where the non-trivial warping arises from the dynamics that stabilizes the size of the extra dimension. Generically, the lightest Kaluza-Klein (KK) particle is the first excitation of the radion field, while the next-to-lightest Kaluza-Klein particle is either the first excitation of the (RH) top quark or the first KK-parity odd Higgs. All these masses are expected to be of order the electroweak scale. We present simple analytical expressions for the masses and wavefunctions of the lowest lying KK modes, and derive the Feynman rules n…
Warped compactifications of type IIB string theory contain natural dark matter candidates: Kaluza-Klein modes along approximate isometry directions of long warped throats. These isometries are broken by the full compactification, including moduli stabilization; we present a thorough survey of Kaluza-Klein mode decay rates into light supergravity modes and Standard Model particles. We find that these dark matter candidates typically have lifetimes longer than the age of the universe. Interestingly, some choices for embedding the Standard Model in the compactification lead to decay rates large e…
We show that in brane-world scenarios with warped extra dimensions, the Casimir force due to bulk matter fields may be sufficient to stabilize the radion field $ϕ$. In particular, we calculate one loop effective potential for $ϕ$ induced by bulk gravitons and other possible massless bulk fields in the Randall-Sundrum background. This potential has a local extremum, which can be a maximum or a minimum depending on the detailed bulk matter content. If the parameters of the background are chosen so that the hierarchy problem is solved geometrically, then the radion mass induced by Casimir correct…
I study a class of Randall-Sundrum (RS) models with Spontaneous Breaking of Scale Invariance (SBSI). This class of models implements the Contino-Pomarol-Rattazzi (CPR) mechanism to achieve SBSI through the small running of an external close-to-marginal scale-breaking operator that leads to a light dilaton/radion with couplings to matter suppressed by the small running. I show that for radion masses $\lesssim 1$ KeV, it can serve as a Dark Matter (DM) candidate, with a lifetime longer than the age of the universe, and show that the experimental bounds from LHC, Non-Newtonian Gravity and Axion-L…
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 study for the first time the case in which Dark Matter (DM) is made of Feebly Interacting Massive Particles (FIMP) interacting just gravitationally with the standard model particles in an extra-dimensional Randall-Sundrum scenario. We assume that both the dark matter and the standard model are localized in the IR-brane and only interact via gravitational mediators, namely the graviton, the Kaluza-Klein gravitons and the radion. We found that in the early Universe DM could be generated via two main processes: the direct freeze-in and the sequential freeze-in. The regions where the observed D…
We explore, within the warped extra dimensional framework, the possibility of finding anti-matter signals in cosmic rays (CRs) from dark matter (DM) annihilation. Exchange of order 100 GeV radion, an integral part of our setup, generically results in Sommerfeld enhancement of the annihilation rate for TeV DM mass. No dark sector is required to obtain boosted annihilation cross sections. A mild hierarchy between the radion and DM masses can be natural due to the pseudo-Goldstone boson nature of the radion. Implications of Sommerfeld enhancement in warped grand unified theory (GUT) models, where…
We consider a (long-lived) sterile neutrino dark matter scenario in a five dimensional (5D) warped extra dimension model where the fields can live in the bulk, which is partly motivated from the absence of the absolutely stable particles in a simple Randall-Sundrum model. The dominant production of the sterile neutrino can come from the decay of the radion (the scalar field representing the brane separation) around the electroweak scale. The suppressions of the 4D parameters due to the warp factor and the small wave function overlaps in the extra dimension help alleviate the exceeding fine-tun…
A radion in a scenario with a warped extra dimension can be lighter than the Higgs boson, even if the Kaluza-Klein excitation modes of the graviton turn out to be in the multi-TeV region. The discovery of such a light radion would be gateway to new physics. We show how the two-photon mode of decay can enable us to probe a radion in the mass range 60 - 110 GeV. We take into account the diphoton background, including fragmentation effects, and include cuts designed to suppress the background to the maximum possible extent. Our conclusion is that, with an integrated luminosity of 3000 $\rm fb^{-1…
Recently (arXiv:1608.00526), a new framework for warped higher-dimensional compactifications with "bulk" standard model (SM) was proposed: in addition to the UV (Planck scale) and IR (a couple of TeV) branes, there is an intermediate brane, taken to be around 10 TeV. The SM matter and Higgs fields propagate from the UV brane down to this intermediate brane only, while gauge and gravity fields propagate in the entire bulk. Such a configuration renders the lightest gauge Kaluza-Klein (KK) states within LHC reach, simultaneously satisfying flavor and CP constraints. In addition, the usual leading…
We revisit the case of scalar dark matter interacting just gravitationally with the Standard Model (SM) particles in an extra-dimensional Randall-Sundrum scenario. We assume that both, the dark matter and the Standard Model, are localized in the TeV brane and only interact via gravitational mediators, namely the graviton Kaluza-Klein modes and the radion. We analyze in detail the dark matter annihilation channel into two on-shell KK-gravitons, and contrary to previous studies which overlooked this process, we find that it is possible to obtain the correct relic abundance for dark matter masses…
Based on the results from numerous astrophysics experiments, it is currently believed that the majority of matter in the Universe is in some unknown form, known as dark matter. In the past it has been common to model dark matter as a massive particle with weak interactions - either from existing Standard Model forces or from new forces - and often as past of a more complicated theory. In this article, an alternative is presented in which dark matter is in the form of a massive particle with no explicit interactions. It is demonstrated that, in the presence of strongly warped extra dimensions t…
The recent PAMELA and ATIC/Fermi/HESS experiments have observed an excess of electrons and positrons, but not anti-protons, in the high energy cosmic rays. To explain this result, we construct a decaying hidden dark matter model in string theory compactification that incorporates the following two ingredients, the hidden dark matter scenario in warped compactification and the phenomenological proposal of hidden light particles that decay to the Standard Model. In this model, on higher dimensional warped branes, various warped Kaluza-Klein particles and the zero-mode of gauge field play roles o…
We analyze signals at the Large Hadron Collider (LHC) from production and decay of Kaluza-Klein (KK) gravitons in the context of "extended" warped extra-dimensional models, where the standard model (SM) Higgs and fermion fields are restricted to be in-between the usual ultraviolet/Planck brane and a $\sim O(10)$ TeV (new, "intermediate") brane, whereas the SM gauge fields (and gravity) propagate further down to the $\sim O( \hbox{TeV} )$ infrared brane. Such a framework suppresses flavor violation stemming from KK particle effects, while keeping the KK gauge bosons and gravitons accessible to …
We study the single graviton production at the CERN LHC using the $k_T$-factorization approach of QCD. We consider the Arkani-Hamed-Dimopoulos-Dvali scenario and Randall-Sundrum model with one warped extra-dimension and derive the production amplitudes for spin-$2$ (Kaluza-Klein excitation of the graviton) and spin-$0$ (radion) states, including subsequent graviton decay into the dilepton or diphoton pairs. We use the transverse momentum dependent (unintegrated) parton densities in a proton obtained from Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equation, which resums the leading lo…
We study the spin-dependence of Dark Matter (DM) particles which interact gravitationally with the Standard Model (SM) in an extra-dimensional Randall-Sundrum scenario. We assume that both the Dark Matter and the Standard Model are confined to the TeV (Infra-red) brane and only interact via gravitational mediators, namely Kaluza-Klein gravitons and the radion. We analyze the different DM annihilation channels and find that it is possible to achieve the presently observed relic abundance of Dark Matter, $Ω_{\rm DM}$, within the freeze-out mechanism for DM particles of spin 0, 1/2 and 1. We stud…
Supersymmetric models with a warped fifth spatial dimension can solve the hierarchy problem, avoiding some shortcomings of non-supersymmetric constructions, and predict a plethora of new phenomena at typical scales Lambda not far from the electroweak scale (Lambda ~ a few TeV). In this paper we derive the low-energy effective theories of these models, valid at energies below Lambda. We find that, in general, such effective theories can deviate significantly from the Minimal Supersymmetric Standard Model (MSSM) or other popular extensions of it, like the NMSSM: they have non-minimal Kaehler pot…
We point out that if the sector associated with the Standard Model degrees of freedom entered an open string Hagedorn phase in the early universe while the dark radiation sector was not part of this plasma, then this can lead to low values of the observable $ΔN_{\text{eff}}$ (number of additional neutrinolike species) from the dark radiation. For explicit analysis, we focus on warped string compactifications with the Standard Model degrees of freedom at the bottom of a warped throat. If the Hubble scale during inflation is above the warped string scale associated with the throat, then the Stan…
Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)（高能加速器研究机构粒子核研究所在）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学）；Department of Physics, College of Humanities and Sciences, Nihon University（日本大学文理学部物理学科）；Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理研究所引力物理与量子信息研究中心）；Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University（名古屋大学小林-益川粒子宇宙起源研究所）
In this work we point out that the apparent diphoton excess initially presented by the ATLAS and CMS collaborations could have originated from a radion in the bulk Higgs scenario within a warped extra dimension. In this scenario the couplings of the radion to massive gauge bosons are suppressed, allowing it to evade existing searches. In the presence of mixing with the Higgs, due to the strong constraints from diboson searches, only points near what we denominate the alignment region were able to explain the diphoton signal and evade other experimental constraints. In light of the new measurem…
We show that the redshift of pressureless matter density due to the expansion of the universe generically induces small oscillations in the stabilized radius of extra dimensions (the radion field). The frequency of these oscillations is proportional to the mass of the radion and can have interesting cosmological consequences. For very low radion masses $m_b$ ($m_b\sim10-100 H_0\simeq10^{-32} eV$) these low frequency oscillations lead to oscillations in the expansion rate of the universe. The occurrence of acceleration periods could naturally lead to a resolution of the coincidence problem, wit…
The chameleon mechanism is a way to give an effective mass to a light scalar field via field self-interaction and interaction with matter. We study this mechanism in models in which the couplings are field dependent and find that the properties are very different from the case of constant couplings. The consequence of a runaway potential for the radion field in brane world scenarios and whether the radion can play the role of dark energy is investigated. The cosmological evolution during the inflationary epoch, the radiation and the matter dominated epochs are discussed as is the compatibility…
It is pointed out that in the warped string compactification, motion of anti-D-branes near the bottom of a throat behaves like dark matter. Several scenarios for production of the dark matter are suggested, including one based on the D/anti-D interaction at the late stage of D/anti-D inflation.
We present a 5D $\mathbb{Z}_2$-symmetric IR-UV-IR model with a {\it warped KK-parity} under which the bulk fields have towers of either even or odd KK-modes. We show that this $\mathbb{Z}_2$-symmetric geometry is equivalent to two times the UV-IR geometry (Randall-Sundrum model) provided each bulk field is subject to Neumann (or mixed) and Dirichlet boundary conditions at the UV-brane for even and odd fields, respectively. The 5D Standard Model (SM) bosonic sector is considered, such that in the 4D low-energy effective theory the $\mathbb{Z}_2$-even zero-modes correspond to the SM degrees of f…
We show that a discrete exchange symmetry can give rise to realistic dark matter candidates in models with warped extra dimensions. We show how to realize our construction in a variety of models with warped extra dimensions and study in detail a realistic model of Gauge-Higgs Unification/composite Higgs in which the observed amount of dark matter is naturally reproduced. In this model, a realistic pattern of electroweak symmetry breaking typically occurs in a region of parameter space in which the fit to the electroweak precision observables improves, the Higgs is heavier than the experimental…
Five-dimensional braneworld constructions in anti-de Sitter space naturally lead to dark sector scenarios in which parts of the dark sector vanish at high 4d momentum or temperature. In the language of modified gravity, such feature implies a new mechanism for hiding light scalars, as well as the possibility of UV-completing chameleon-like effective theories. In the language of dark matter phenomenology, the high-energy behaviour of the mediator sector changes dark matter observational complementarity. A multitude of signatures---including exotic ones---are present from laboratory to cosmologi…
