In most multi-component dark-matter scenarios, two classes of processes generically contribute to event rates at experiments capable of probing the nature of the dark sector. The first class consists of "diagonal" processes involving only a single species of dark-matter particle -- processes analogous to those which arise in single-component dark-matter scenarios. By contrast, the second class consists of "off-diagonal" processes involving dark-matter particles of different species. Such processes include inelastic scattering at direct-detection experiments, asymmetric production at colliders, dark-matter co-annihilation, and certain kinds of dark-matter decay. In typical multi-component scenarios, the contributions from diagonal processes dominate over those from off-diagonal processes. Unfortunately, this tends to mask those features which are most sensitive to the multi-component nature of the dark sector. In this paper, by contrast, we point out that there exist natural, multi-component dark-sector scenarios in which the off-diagonal contributions actually dominate over the diagonal. This then gives rise to a new, enhanced picture of dark-matter complementarity. In this paper, we introduce a scenario in which this situation arises and examine the enhanced picture of dark-matter complementarity which emerges.
Low and High Energy Phenomenology of Quark-Lepton Complementarity Scenarios
我们进行了详细的分析的现象学的两个预测跷跷板的情况下，导致夸克-轻子互补。在这两种情况下，我们讨论了中微子混合观测量及其关联，无中微子双β衰变和轻子味违反衰变，如μ-> e γ。我们还评论leptogenesis。第一种情况在一到两个标准差的水平上是不利的，特别是由于其对U_{e3}的预测。准简并的重中微子和轻中微子可以产生共振轻生，这意味着在无中微子的双β衰变中会有相当大的抵消。衰变μ-> e γ和τ-> μ γ通常是可观察到的，除非超对称质量接近TeV标度。在第二种情况下，瘦生是不可能的。然而，它与所有振荡数据完全一致。除非超对称质量在几个TeV的范围内，否则对μ-> e γ的预测通常太大。在这种情况下，tau -> e gamma和tau -> mu gamma是不可观察的。
We describe current and future hadron collider limits on new vector-like leptons with exotic decays. We consider the possibility that, besides standard decays, the new leptons can also decay into a Standard Model charged lepton and a stable particle like a dark photon. To increase their applicability, our results are given in terms of arbitrary branching ratios in the different decay channels. In the case that the dark photon is stable at cosmological scales we discuss the interplay between the dark photon and the vector-like lepton in generating the observed dark matter relic abundance and th…
New gauge symmetries often appear in theories beyond the Standard Model. Here we study a model where lepton number is promoted to a gauge symmetry. Anomaly cancellation requires the introduction of additional leptons, the lightest of which is a natural leptophilic dark matter candidate. We perform a comprehensive study of both collider and dark matter phenomenology. Furthermore we find that the model exhibits a first order lepton number breaking phase transition in large regions of parameter space. The corresponding gravitational wave signal is computed, and its detectability at LISA and other…
We discuss the phenomenology of an MeV-scale Dirac fermion coupled to the Standard Model through a dark photon with kinetic mixing with the electromagnetic field. We compute the dark matter relic density and explore the interplay of direct detection and accelerator searches for dark photons. We show that precise measurements of the temperature and polarization power spectra of the Cosmic Microwave Background Radiation lead to stringent constraints, leaving a small window for the thermal production of this MeV dark matter candidate. The forthcoming MeV gamma-ray telescope e-ASTROGAM will offer …
Colored dark sectors where the dark matter particle is accompanied by colored partners have recently attracted theoretical and phenomenological interest. We explore the possibility that the dark sector consists of the dark matter particle and a color-octet partner, where the interaction with the Standard Model is governed by an effective operator involving gluons. The resulting interactions resemble the color analogues of electric and magnetic dipole moments. Although many phenomenological features of this kind of model only depend on the group representation of the partner under SU(3)$_c$, we…
We investigate the phenomenology of a scalar top-philic dark matter candidate when adding a dimension-five contact interaction term, as motivated by possible underlying extensions of the Standard Model such as composite Higgs models. We show that the presence of contact interactions can have a major impact on the dark matter relic density as well as on its direct and indirect detection prospects, while the collider phenomenology of the model is unaffected. This underlines the complementarity of collider and cosmological constraints on dark matter models.
We propose an extension of the Standard Model (SM) with a $U_{A'}(1)$ gauge invariant dark dector connected to the SM via a new portal -- the Stueckelberg portal, arising in the framework of dark photon $A'$ mass generation via Stueckelberg mechanism. This portal opens through the effective dim=5 operators constructed from the covariant term of the auxiliary Stueckelberg scalar field $σ$ providing flavor non-diagonal renormalizable couplings of both $σ$ and $A'$ to the SM fermions $ψ$. The Stueckelberg scalar plays a role of Goldstone boson in the generation of mass of the Dark Photon. Contrar…
After the successful investigation and confirmation of non zero $θ_{13}^{PMNS}$ by various experiments, we are standing at a square where we still encounter a number of issues, which are to be settled. In this paper, we have extended our recent work towards a precise prediction of the $θ_{23}^{PMNS}$ mixing angle, taking into account the neutrino mass hierarchy. We parameterize the non-trivial correlation between quark (CKM) and lepton (PMNS) mixing matrices in quark-lepton complementarity (QLC) model as $V_{c}= U_{CKM}. ψ. U_{PMNS}$, where $ψ$ is a diagonal phase matrix. Monte Carlo simulatio…
We present an extensive analysis of a model in which the (Majorana) Dark Matter candidate is a mixture between a SU(2) singlet and two SU(2) doublets. This kind of setup takes the name of singlet-doublet model. We will investigate in detail an extension of this model in which the Dark Matter sector interactions with a 2-doublet Higgs sector enforcing the complementarity between Dark Matter phenomenology and searches of extra Higgs bosons.
We study a simple extension of the Standard Model that accounts for neutrino masses and dark matter. The Standard Model is augmented by two Higgs doublets and one Dirac singlet fermion, all charged under a new dark global symmetry. It is a generalised version of the Scotogenic Model with Dirac fermion dark matter. Masses for two neutrinos are generated radiatively at one-loop level. We study the case where the singlet fermion constitutes the dark matter of the Universe. We study in depth the phenomenology of the model, in particular the complementarity between dark matter direct detection and …
Anatomy and Phenomenology of Minimal Flavor Deconstruction in the Lepton Sector
Università degli Studi di Padova（帕多瓦大学）；Istituto Nazionale di Fisica Nucleare (INFN)（意大利国家核物理研究所）；Institut de Física Corpuscular (CSIC-Universitat de València)（瓦伦西亚大学与西班牙国家科研中心联合粒子物理研究所）；Universität Zürich（苏黎世大学）
We study the cosmology and LHC phenomenology of a consistent strongly interacting dark sector coupled to Standard Model particles through a generic vector mediator. We lay out the requirements for the model to be cosmologically viable, identify annihilations into dark vector mesons as the dominant dark matter freeze-out process and discuss bounds from direct detection. At the LHC the model predicts dark showers, which can give rise to semi-visible jets or displaced vertices. Existing searches for di-jet resonances and for missing energy mostly probe the parameter regions where prompt decays ar…
We study the phenomenology and detection prospects of a sub-GeV Dirac dark matter candidate with resonantly enhanced annihilations via a dark photon mediator. The model evades cosmological constraints on light thermal particles in the early universe while simultaneously being in reach of current and upcoming terrestrial experiments. We conduct a global analysis of the parameter space , considering bounds from accelerator and direct detection experiments, as well as those arising from Big Bang Nucleosynthesis, the Cosmic Microwave Background and dark matter self-interactions. We also extend our…
MSSM中的轻Higgs质量受到很大的约束，被预测接近于MZ，这导致了114 GeV的LEP II Higgs质量束缚与MSSM中自然的电弱对称性破缺之间的张力。通常增加轻CP甚至Higgs质量的方法是增加上型Higgs的四次耦合。我们指出，轻希格斯质量可以通过减少非对角项的质量矩阵时，tan β是中等的，这是大约5至10。结果，没有混合和/或出现相反符号的希格斯混合角，并且希格斯衰变的分支比急剧改变。这是可能的标量隔离的情况下，其中μ参数可以是大的独立的电弱对称性破缺。我们也讨论了同样的效果在BMSSM。
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…
Multi-level dark matter with diagonal and off-diagonal interactions shows a rich phenomenology in its self-scattering. If the interactions are mediated by a particle that is less massive than the dark matter, Sommerfeld effect can lead to resonant enhancement of the scattering. For mediators lighter than the level separation, dark matter particles can upscatter to excited states and de-excite by emitting these mediators. We compute these cross-sections, both above and below the kinematic threshold, in a generic two-component dark matter model and identify the large inelastic cross-section as a…
The phenomenology of flavor mixing of heavy Majorana neutrinos is studied. The physical degrees of freedom, which propagate like free particles until they decay in the presence of flavor mixing, are identified by diagonalizing the resummed propagator. It is shown that they should be interpreted as quasiparticles which lose Majorana nature.
Simplified Models for Dark Matter Face their Consistent Completions
简化的暗物质模型最近被提倡作为一个强有力的工具，利用暗物质直接探测，间接探测和LHC实验探针之间的互补性。专注于赝标量介质之间的黑暗和可见的部门，我们表明，简化的暗物质模型的现象学偏离一致的${SU(2)_{\mathrm{L}} \times U(1)_{\mathrm{Y}}}$规范不变完成显着。我们讨论了简化模型未能捕捉到的关键物理，以及它对LHC搜索的影响。值得注意的是，我们表明，共振单Z搜索提供竞争力的灵敏度，标准的单射流分析在$13$ TeV LHC。
We present a model for Lepton Flavor Violating (LFV) neutral current non-standard interactions of neutrinos with matter fields parameterized by $ε_{αβ}^f$ with $α\ne β$. Here, unlike the previous models, the ratios of the off-diagonal LFV elements of the effective NSI coupling to the diagonal lepton flavor conserving ones ({\it i.e.,} $(ε_{αβ}^f)^2/(ε_{αα}^f ε_{ββ}^f)$ ) are arbitrary. The model enjoys rich phenomenology, predicting invisible Higgs decay and new meson decay modes observable in upcoming experiments. The model for $ε_{μe}^f$ also predicts a $μ^-$ to $e^-$ conversion rate on nucl…
This report summarizes the present status of neutrino non-standard interactions (NSI). After a brief overview, several aspects of NSIs are discussed, including connection to neutrino mass models, model-building and phenomenology of large NSI with both light and heavy mediators, NSI phenomenology in both short- and long-baseline neutrino oscillation experiments, neutrino cross-sections, complementarity of NSI with other low- and high-energy experiments, fits with neutrino oscillation and scattering data, DUNE sensitivity to NSI, effective field theory of NSI, as well as the relevance of NSI to …
We study freeze-in dark matter production in models that rely on the Clockwork mechanism to suppress the dark matter couplings to the visible sector. We construct viable scalar and fermionic dark matter models within this Clockwork FIMP scenario, with several subtleties that need to be taken into account revealed in the model-building process. We also provide analytic, semi-analytic and numerical results for the diagonalization of Clockwork-type mass matrices and briefly discuss the LHC phenomenology of the corresponding scenarios.
Scrutinizing Fermionic Dark Matter in Scotogenic Model with Low Reheating Temperature
Center for Quantum Spacetime, Sogang University（中央量子时空中心，西江大学）；Department of Physics, Sogang University（物理系，西江大学）；Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha 751005, India（奥里萨邦布巴内斯瓦尔萨奇瓦拉亚马格物理学研究所）；Homi Bhabha National Institute, BARC Training School Complex, Anushakti Nagar, Mumbai 400094, India（霍米·巴巴国立学院，BARC培训学院综合体）
We investigate the phenomenology of scalar singlet dark matter candidates that couple dominantly to the Standard Model via a Yukawa interaction with the top quark and a colored vector-like fermion. We estimate the viability of this vector-like portal scenario with respect to the most recent bounds from dark matter direct and indirect detection, as well as to dark matter and vector-like mediator searches at colliders. Moreover, we take QCD radiative corrections into account in all our theoretical calculations. This work complements analyses related both to models featuring a scalar singlet coup…
