Generic extensions of the Standard Model that respect baryon and lepton numbers have accidentally stable particles. Typical examples are the lightest exotic neutral fermion, or "neutralino", and fields with non-trivial lepton and baryon charges. In this paper we show that an accidentally stable neutralino is a natural dark matter candidate in models with warped extra dimensions. We find that annihilation into other Kaluza-Klein resonances is often allowed and very efficient. The observed dark matter abundance may then be obtained with couplings of order unity and a compactification scale above the TeV. Light dark matter is also possible in the presence of unsuppressed couplings to the Higgs boson. In this latter case direct detection experiments will soon be able to probe a significant portion of the parameter space.
A classically scale-invariant scalar singlet can be a MeV-scale dark matter, with a feeble Higgs portal coupling at $\mathcal{O}(10^{-10})$. Besides, an $\mathcal{O}(0.1)$ self-interaction coupling could further serve to alleviate the small-scale problems in the Universe. We show that, such a dark matter candidate can naturally arise in the warped extra dimension, with the huge span of parameter space predicted well within $\mathcal{O}(1)$ fundamental parameters.
While the warped extra-dimensional models provide an attractive solution to both the gauge and the flavor hierarchy problems, the mass scale of new particles predicted by the minimal models would be beyond the reach of the LHC. Models of extended warped extra dimensions have been proposed to evade these issues and their collider implications have been investigated for the last decade. This white paper summarizes the recent developments in the context of collider phenomenology. The strategies and lessons are broad, and provide a template to extend the experimental program, to cover a wider clas…
Warped Extra Dimension scenarios are a rich playground for phenomenology of heavy resonances at LHC. The Radion and the KK-graviton are inevitable signatures of this class of models. On face of the latest LHC experimental results on the direct searches for Beyond Standard Model physics we update the phenomenological predictions for production and decay of such resonances in its main production modes. We also highlight the phenomenology results relevant to collider searches in individual channels, and provide tools for interpretation of current and future experimental analyses using two specifi…
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 …
The recent B-meson anomalies are coherently explained at the TeV scale by 4321 gauge models with hierarchical couplings reminiscent of the Standard Model Yukawas. We show that such models arise as the low-energy limit of a complete theory of flavor, based on a warped fifth dimension where each Standard Model family is quasi-localized in a different brane. The Higgs is identified as a pseudo-Nambu-Goldstone boson emerging from the same dynamics responsible for 4321 symmetry breaking. This novel construction unifies quarks and leptons in a flavor non-universal manner, provides a natural descript…
Light sterile neutrinos are a popular extension of the Standard Model and are being discussed as a possible explanation for various neutrino oscillation anomalies, including the LSND, MiniBooNE, Reactor and Gallium anomalies. In order to avoid inconsistencies with constraints derived from disappearance experiments and cosmology, altered dispersion relations - which may originate from extra dimensions - have been proposed as a possible solution, dubbed as "neutrino shortcuts in the extra dimension". In this paper we develop a neutrino mass model with an asymmetrically warped extra dimension and…
We study dark matter interacting via a massive spin-2 mediator. To have a consistent effective theory for the spin-2 particle, we work in a warped extra-dimensional model such that the mediator(s) are the Kaluza-Klein (KK) modes of the 5D graviton. We pay close attention to dark matter annihilations into KK-gravitons. Due to the high energy behavior of longitudinal modes of spin-2 fields, these channels exhibit a tremendous growth at large center of mass energies $\sqrt{s}$ if only one spin-2 mediator is considered. For the first time, we include the full KK-tower in this dark matter productio…
In this thesis, we have studied the possibility to identify one of the right-handed neutrinos entering the type-I seesaw mechanism as a Dark Matter (DM) candidate, within the warped extra-dimensions paradigm. As a first step, we have reviewed the existing literature on the Randall-Sundrum scenarios and the Goldberger-Wise stabilization mechanism. We have discussed a feasible realization of the type-I seesaw mechanism, implemented by warped compactification of an extra dimension. Taking advantage of recent studies, we have explored how the thermal DM can be included in the warped scenario. We h…
Supersymmetric dark matter has been studied extensively in the context of the MSSM, where gauginos have Majorana masses. Introducing Dirac gaugino masses, we obtain an enriched phenomenology from which considerable differences in, e.g., LHC signatures can be expected. Concretely, in the Minimal Dirac Gaugino Model (MDGSSM) we have an electroweakino sector extended by two extra neutralinos and one extra chargino. The bino- and wino-like states bring about small mass splittings leading to the frequent presence of scenarios with Long Lived Particles (LLPs). In this contribution, we delineate the …
A Model of Lepton Masses from a Warped Extra Dimension
为了解释非层次中微子混合角和在弯曲额外维的背景下轻子味违反过程的缺乏，需要引入体味对称性。基于A4非阿贝尔离散对称性，我们给出了一个简单的RS模型中轻子质量和混合的模型。这种选择的优点是：（i）自然出现的三-双极大的混合模式;（ii）在中性部门的树级味违反完全没有;（iii）味规范玻色子的情况下;（iv）层次的带电轻子质量解释通过波函数重叠。我们提出了最小的字段内容和对称性破缺模式，以获得成功的这种类型的模型。从电弱精密测量的界限允许KK质量尺度低至3 TeV。在这个模型中不存在树级轻子味破坏，而环诱导的μ-> e γ分支分数安全地低于实验界限。
Collider Signals of Top Quark Flavor Violation from a Warped Extra Dimension
在弯曲额外维的框架下，研究了标准模型（SM）场中的顶夸克味破坏。这样的方案提供了解决方案，普朗克弱层次问题和味道难题的SM没有诱导的味道问题。我们发现，一般来说，tcZ耦合得到了巨大的增强，特别是右手的可以是O（1%）。这导致BR（t -> c Z）等于或高于大型强子对撞机（LHC）的灵敏度。在国际直线对撞机（International Linear Collider，ILC）上，通过e^+ e^- -> t \bar c的单顶产生可能是这种情况的一个显著信号。特别是，它代表了一个非常重要的物理学主题，即使是在接近tc阈值的相对低的能量选项下也可以进行探索。在LHC和ILC中，角分布可以探测上述右手耦合主导的预测。
