本文详细研究了含类轴子粒子的 3-3-1 模型的标量部门，证明了双轻子与普通标量场无混合，确定了类轴子粒子和 100 GeV-1 TeV 赝标量的物理场，并验证了模型在顶夸克衰变、Higgs 轻子衰变和介子振荡中符合实验约束。
摘要：
本文详细研究了含类轴子粒子的 3-3-1 模型的标量部门。在所考虑的模型中，存在两种标量场：携带轻子数为 2 的双轻子标量场和不携带轻子数的普通标量场。我们证明这两种标量场之间不存在混合。我们详细分析了该模型的 CP 奇标量部门，以寻找类轴子粒子的物理场以及质量在 100 GeV 到 1 TeV 范围内的赝标量。所得结果与之前已发表的研究不同。本文还分析了该模型的 CP 偶标量部门。我们对标量部门的分析结果允许我们将标量质量容纳在 100 GeV 至 1 TeV 的区域内。此外，我们分析了该模型在顶夸克的几种味改变中性衰变以及顶夸克稀有衰变中的物理意义。除此之外，还分析了类 SM Higgs 玻色子的轻子衰变以及介子振荡。我们的数值分析表明，所考虑的模型与这些过程所施加的实验约束相一致。
英文摘要：
The scalar sector of the 3-3-1 model with axion like particle is studied in detail. In the model under consideration, there are two kinds of scalar fields: the bilepton scalars carrying lepton number two and the ordinary ones without lepton number. We show that there is no mixing among these two kinds of scalar fields. We analyze in detail the CP-odd scalar sector of the model to find the physical fields of the axion like particle and a pseudoscalar with mass in the range 100 GeV to 1 TeV. The results are different from others which have been published before. The CP-even scalar sector of the model is analyzed as well. The results of our analysis of the scalar sector allow us to accommodate scalar masses in the $100$ GeV-$1$ TeV region. Furthermore we analyze the implications of the model in several flavor changing neutral decays of the top quark as well as in rare top quark decays. Besides that, the leptonic decays of the SM like Higgs boson as well as the meson oscillations are also analyzed. Our numerical analysis show that the model under consideration is consistent with the experimental constraints imposed by these processes.
We investigate the phenomenology of QCD axions and axionlike particles in a scenario with two eras of inflation. In particular, we describe the possible solutions for the QCD axion field equation after the second inflation and reheating. We calculate the dilution numerically for QCD axions and give an analytic approximation for axionlike particles. While it has been realised before that such a scenario can dilute the axion energy density and open up the parameter space for the axion decay constant $f_A$, we find that even a small increase in the relative QCD axion energy density is possible.
We show that an axionlike particle (ALP) naturally implements spontaneous electroweak baryogenesis through a cosmic evolution strongly tied to the electroweak phase transition (EWPT) if it feebly couples to the Higgs field while giving a small contribution to the Higgs boson mass. The observed baryon asymmetry can be generated successfully if the ALP couples strongly enough to the electroweak anomaly. Also interesting is that the ALP contributes to dark matter, and its coupling to a hidden gauge sector makes the relic abundance insensitive to the cosmic history before the EWPT. The ALP explain…
We will investigate the scenario in which the Standard Model (SM) Higgs sector and its 2-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints purely coming from DM phenomenology with more general constraints like Electro-weak Precision Tests (EWPT) as well as with collider searches. In the case that the n…
We perform a phenomenological study of the scalar sector of two models that generate neutrino mass at the three-loop level and contain viable dark matter candidates. Both models contain a charged singlet scalar and a larger scalar multiplet (triplet or quintuplet). We investigate the effect of the extra scalars on the Higgs mass and analyze the modifications to the triple Higgs coupling. The new scalars can give observable changes to the Higgs decay channel $h\rightarrowγγ$ and, furthermore, we find that the electroweak phase transition becomes strongly first-order in large regions of paramete…
We discuss a model with a dark sector, in which smallness of mass for charged leptons and neutrinos can naturally be explained by one-loop effects mediated by particles in the dark sector. These new particles, including dark matter candidates, also contribute to the anomalous magnetic dipole moment, denoted by $(g-2)$, for charged leptons. We show that our model can explain the muon $(g-2)$ anomaly and observed neutrino oscillations under the constraints from lepton flavor violating decays of charged leptons. We illustrate that the scenario with scalar dark matter is highly constrained by dire…
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…
We consider the doublet-triplet fermionic model in the scheme of the custodial limit when the dark matter (DM) candidate is pure doublet and lies at the electroweak scale. This scheme, despite being an appealing and promising DM model, is severely constrained by the interplay between the DM relic density constraint and the LHC measurement of the Higgs diphoton decay rate. In this work, the DM relic density is considered to arise from either a nonstandard cosmology scenario or as a part of a larger sector encompassing other DM particles, this in order to saturate the observed relic abundance. F…
In this paper, we revisit the dimension-7 neutrino mass generation mechanism based on the addition of an isospin $3/2$ scalar quadruplet and two vector-like iso-triplet leptons to the standard model. We discuss the LHC phenomenology of the charged scalars of this model, complemented by the electroweak precision and lepton flavor violation constraints. We pay particular attention to the triply charged and doubly charged components. We focus on the same-sign-tri-lepton signatures originating from the triply-charged scalars and find a discovery reach of 600 - 950 GeV at 3 ab$^{-1}$ of integrated …
A natural avenue to extend the Standard Model (SM) is to embed it into a more symmetric framework. Here, I focus in Left-Right (LR) Models, which treat left- and right-handed chiralities on equal footing. Important information about the structure of LR Models comes from meson-mixing observables. Due to the impact of the new contributions to these processes, I consider the calculation of the short-distance QCD effects correcting the LR Model contributions to meson-mixing observables at the Next-to-Leading Order. I then revisit the phenomenology of a simple realization of LR Models, containing d…
If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of massive, likely $\gsim 1$ TeV, enabler portal matter (PM) particles that carry both dark and SM quantum numbers which will appear in vacuum polarization-like loop graphs. Such heavy states are only directly accessible at high energy colliders and apparently lie at mass scales beyond the direct kinematic reach of the ILC, CEPC and FCC-ee. A likely possibility is that these new particles are part of the 'next step' toward a UV-complete scenario describing both the SM an…
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 explore the phenomenology of a unique three-Higgs-doublet model based on the single CP symmetry of order 4 (CP4) without any accidental symmetries. The CP4 symmetry is imposed on the scalar potential and Yukawa interactions, strongly shaping both sectors of the model and leading to a very characteristic phenomenology. The scalar sector is analyzed in detail, and in the Yukawa sector we list all possible CP4-symmetric structures which do not run into immediate conflict with experiment, namely, do not lead to massless or mass-degenerate quarks nor to insufficient mixing or CP-violation in the…
The Hidden Abelian Higgs Model (HAHM) is an extension of the Standard Model based on the gauge group $G =SU(3)_{C} \times SU(2)_{L} \times U(1)_{Y} \times U(1)_{X}$ i.e. an extra $U(1)_{X}$ gauge group in addition to the SM gauge groups.In HAHM, an Abelian Hidden sector is coupled to the SM, and the resulting new Higgs boson H and new neutral gauge boson $Z_{HAHM}$ fields are allowed to mix with the corresponding SM fields. In this work, we search for the new neutral gauge boson $Z_{HAHM}$ and new Higgs boson in the context of the Hidden Abelian Higgs Model (HAHM) through the decay process $pp…
Colored dark sectors where the dark matter particle is accompanied by colored partners have recently attracted theoretical and phenomenological interest. We explore the possibility that the dark sector consists of the dark matter particle and a color-octet partner, where the interaction with the Standard Model is governed by an effective operator involving gluons. The resulting interactions resemble the color analogues of electric and magnetic dipole moments. Although many phenomenological features of this kind of model only depend on the group representation of the partner under SU(3)$_c$, we…
I present a class of hidden sector dark matter (DM) models with local dark gauge symmetries, where DM is stable due to unbroken local dark gauge symmetry, or due topology, or it is long-lived because of some accidental symme- tries, and the particle contents and their dynamics are completely fixed by local gauge symmetries. In these models, one have two types of natural force mediators, dark gauge bosons and dark Higgs boson, which would affect DM and Higgs phenomenology in important ways. I discuss various phenomenological issues including the GeV scale gamma-ray excess from the galactic cent…
Continuum supersymmetry is a class of models in which the supersymmetric partners together with part of the standard model come from a conformal sector, broken in the IR near the TeV scale. Such models not only open new doors for addressing the problems of the standard model, but also have unique signatures at hadron colliders, which might explain why we have not yet seen any superpartners at the LHC. Here we use gauge-gravity duality to model the conformal sector, generate collider simulations, and finally analyze continuum gluino signatures at the LHC. Due to the increase in the number of je…
We perform a general study of the relic density and LHC constraints on simplified models where the dark matter coannihilates with a strongly interacting particle X. In these models, the dark matter depletion is driven by the self-annihilation of X to pairs of quarks and gluons through the strong interaction. The phenomenology of these scenarios therefore only depends on the dark matter mass and the mass splitting between dark matter and X as well as the quantum numbers of X. In this paper, we consider simplified models where X can be either a scalar, a fermion or a vector, as well as a color t…
Phenomenology of the Higgs sector from Reduction of Couplings in the Type-II 2HDM
National Centre for Nuclear Research（国家核研究中心）；Centro de Física Teórica de Partículas - CFTP, Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa（里斯本大学高等技术学院物理系粒子理论物理中心）
We present a minimal left-right symmetric flavor model and analyze the predictions for the neutrino sector. In this scenario, the Yukawa sector is shaped by the dihedral $D_4$ symmetry which leads to correlations for the neutrino mixing parameters. We end up with four possible solutions within this model. We further analyzed the impact of the upcoming long-baseline neutrino oscillation experiment DUNE. Due to its high sensitivity, DUNE will be able to rule out two of the solutions. Finally, the prediction for the neutrinoless double beta decay for the model has also been examined.
This Thesis is devoted to the phenomenological analysis at the large hadron collider (LHC), as well at a future electron positron collider, of the 4 dimensional (4D) composite Higgs model (4DCHM), a compelling beyond the standard model scenario where the Higgs state arises as a pseudo Nambu Goldstone boson. The motivations and the main characteristics of the model are summarised and then an analysis of the gauge and Higgs sectors of the 4DCHM is performed. Finally we propose a general framework for the analysis of models with an extended quark sector that we have applied to a simplified compos…
We analyze the neutrino phenomenology in an $SU(5)$ F-theory model with both a visible sector and a twin hidden sector. At low energies, the strong and weak scales of the two sectors may differ but the spectrum of states is described by the MSSM (MSSM$^\prime$) in the visible (twin) sectors. What is special about the model is that there are right-handed neutrinos which couple to both sectors via Yukawa couplings. As a result, assuming 3 right-handed neutrinos with a large mass much greater than the weak scale, at tree-level the seesaw mechanism results in 3 massive Majorana neutrinos and 3 mas…
On the Phenomenology of Strongly Coupled Hidden Sectors
在超对称性破缺和介导模型中，强耦合超对称性破缺扇区在确定模型低能谱中起着重要作用。例如，强动力学可以为超对称性问题和mu / B mu问题提供自然的解决方案。最近，有人建议，一个大类的这些模型导致相同的边界条件在超对称性破缺尺度。这些边界条件将严重限制模型的可行性。我们证明，边界条件，而不是敏感的隐藏部门的细节，只有特定的隐藏部门可能会被排除的现象学考虑。我们利用隐扇区的算子乘积展开确定了高尺度边界条件。用于确定β函数的技术通常适用于任意近似共形隐扇区的RG流。与以前提出的边界条件的差异可以追溯到这样一个事实，即重整化群（RG）流涉及多个固定点。
We consider the phenomenological implications of charged scalar extensions of the SM Higgs sector in addition to EFT couplings of this new state to SM matter. We perform a detailed investigation of modifications of loop-induced decays of the 125 GeV Higgs boson, which receives corrections from the propagating charged scalars alongside one-loop EFT operator insertions and demonstrate that the interplay of $H\to γγ$ and $H\to Zγ$ decays can be used to clarify the additional states phenomenology in case a discovery is made in the future. In parallel, EFT interactions of the charged Higgs can lead…
A light boson $U$ from an extra $U(1)$ interpolates between a generalized dark photon coupled to $Q,\ B$ and $L_i$ (or $B-L$), plus possibly dark matter, a dark $Z$ coupled to the $Z$ current, and one axially coupled to quarks and leptons. We identify the corresponding $U(1)_F$ symmetries, with $F= γ_Y Y+γ_B B+γ_{L_i}L_i+γ_A F_A+γ_{F'}F'\!+γ_d F_d$, $F_d$ acting in a dark sector and $F'$ on possible semi-inert BEH doublets uncoupled to quarks and leptons. The $U$ current is obtained from the $U(1)_F $ and $Z$ currents, with a mixing determined by the spin-0 BEH fields. The charge $Q_U$ of chir…
