Top-partners -- vector-like quarks which mix predominantly with the top quark -- are simple extensions of the standard model present in many theories of new physics such as little Higgs models, topcolor models, and extra dimensions. Through renormalizable mixing with the top quark, these top-partners inherit couplings to the Higgs boson. Higgs bosons produced from the decay of top-partners are often highly boosted and ideal candidates for analyses based on jet substructure. Using substructure methods, we show that light Higgs bosons decaying to b b-bar can be discovered at the 14 TeV LHC with less than 10 inverse fb for top-partner masses up to 1 TeV.
We consider a particular composite Higgs model which contains SU(3) color octet top partners besides the usually considered triplet representations. Moreover, color singlet top partners are present as well which can in principle serve as dark matter candidates. We investigate the LHC phenomenology of these unusual top partners. Some of these states could be confused with gluinos predicted in supersymmetric models at first glance.
Composite Higgs models with a fermionic UV completion can contain additional colored states beside the usual top-partners. We focus here on a model which contains in addition SU(3) color octet top partners as well as color singlet ones. The latter can in principle serve as a dark matter candidate. We consider a particular composite Higgs model which contains SU(3) color octet top partners besides the usually considered triplet representations. Moreover, color singlet top partners are present as well which can in principle serve as dark matter candidates. We investigate the LHC phenomenology of…
Improving sensitivity of vectorlike top partner searches with jet substructure
Indian Institute of Technology Guwahati（印度理工学院古瓦哈提分校）；Indian Institute of Science Education and Research Kolkata（印度科学教育研究所加尔各答分校）；Indian Institute of Science Education and Research, Knowledge City, Sector 81, S. A. S. Nagar, Manauli PO 140306, Punjab, India（印度科学教育研究所旁遮普邦分校）；The Institute of Mathematical Sciences（数学科学研究所）
In the framework of the littlest Higgs Model with T-parity, we discuss the top partner production at future $e^{+}e^{-}$ collider. We calculate the cross sections of the top partner production processes and associated production processes of Higgs and top partner under current constraints. Then, we investigate the observability of the T-odd top partner pair production through the process $e^{+}e^{-}\rightarrow T_{-}\bar{T}_{-}\rightarrow t\bar{t}A_{H}A_{H}$ in the $t\bar{t}$ di-lepton channel for two T-odd top partner mass $m_{T_{-}}$=603(708) GeV at $\sqrt{s}$=1.5 TeV. We analyze the signal s…
In this paper we explore composite Higgs scenarios through the effects of light top-partners in Higgs+Jet production at the LHC. The pseudo-Goldstone boson nature of the Higgs field means that single-Higgs production via gluon fusion is insensitive to the mass spectrum of the top-partners. However in associated production this is not the case, and new physics scales may be probed. In the course of the work we consider scenarios with both one and two light top-partner multiplets in the spectrum of composite states. We study corrections to the Higgs couplings and the effects that the light top-p…
LHC searches for heavy neutral Higgs bosons with a top jet substructure analysis
在一般双Higgs模型下，研究了重$CP$ -奇希格斯玻色子$A$和重$CP$ -偶希格斯玻色子$H$的LHC搜索.具体而言，我们考虑通过$b \bar b$或$t \bar t $相关的生产渠道的$A/H\to t \bar t $的衰减模式。在所谓的“排列极限”的两个希格斯偶线模型，这种衰变模式可以是最主要的一个。通过使用HEPTopTagger和多变量分析方法，我们给出了在高亮度LHC运行中通过这些通道对$CP$ -奇希格斯玻色子$A$和$CP$ -偶希格斯玻色子$H$的搜索灵敏度.
Manifest gauge-invariance requires that observable states in the standard-model are described by composite operators, which involve additional Higgs contributions beyond perturbation theory. This field-theoretical effect has been confirmed in lattice simulations. It should also be experimentally accessible at high enough precision. Here a few estimates for such signatures at current and future collider experiments will be discussed.
Guided us by the scenario of weak scale naturalness and the possible existence of exotic resonances, we have explored in a $SO(5)$ Composite Higgs set-up the interplay among three matter sectors: elementary, top partners and vector resonances. We parametrise it through explicit interactions of spin-1 $SO(4)$-resonances, coupled to the $SO(5)$-invariant fermionic currents and tensors presented in this work. Such invariants are built upon the Standard Model fermion sector as well as top partners sourced by the unbroken $SO(4)$. The mass scales entailed by the top partner and vector resonance sec…
We examine a model with multiple scalar fields to see whether it is possible to reduce the fine- tuning of the SM Higgs mass without introducing low scale top partners. Our approach may be regarded as a generalization of the condition proposed by Veltman, who attempted to predict the Higgs mass using the criterion that the various low energy contributions to the quadratic divergence of the Higgs mass cancel. Although the Veltman condition predicts the wrong Higgs mass in the Standard Model, it can still be adapted to extended Higgs sectors. Furthermore, theories with additional Higgs bosons ca…
In the littlest Higgs Model with T-parity, we discuss the pair production of the T-odd top partner ($T_{-}$) which decays almost 100\% into the top quark and the lightest T-odd particle ($A_{H}$). Considering the current constraints, we investigate the observability of the T-odd top partner pair production through the process $pp\rightarrow T_{-}\bar{T}_{-}\rightarrow t\bar{t}A_{H}A_{H}$ in final states with two leptons at 14 TeV LHC. We analyze the signal significance and find that the lower limit on the T-odd top partner mass are about 1.04 TeV, 1.14 TeV, 1.23 TeV at $2σ$ confidence level at…
Searching for Heavy Charged Higgs Boson with Jet Substructure at the LHC
我们研究了在大型强子对撞机上产生的重荷希格斯玻色子（在这项研究中从800 GeV到1500 GeV）与顶夸克的碰撞能量为$\sqrt{s}=14$ TeV。这样一个重电荷的希格斯玻色子玻色子由于其大的汤川耦合，可以像MSSM一样主要衰变为顶夸克和底夸克。为了抑制背景事件并确认信号，我们重建了重电荷希格斯玻色子和相关顶夸克的质量隆起。为此，我们提出了一种混合R重建方法，它利用顶部标记技术，射流子结构技术开发的高度提升大质量粒子。以$p p \to H^{\pm} t \to t tb$的全强子模作为测试场，我们发现这种方法可以大大减少全重构中的组合运算，并成功地将背景事件降低到一个可控的水平。研究了LHC对重荷希格斯玻色子的灵敏度，发现当$b$时，能达到$9.5σ$意义.
The Global Higgs as a Signal for Compositeness at the LHC
复合Higgs模型中的整体破缺真空的径向激发，被称为“整体Higgs”，是近年来的研究热点。在本文中，我们研究了在13 TeV LHC检测这种复合标量的前景。我们计算了全球希格斯粒子的产生率，并估计了全球希格斯粒子衰变成顶夸克对和希格斯粒子和电弱规范玻色子以及随后的强子衰变的发现潜力。整体希格斯粒子也可能衰变为费米子共振，如顶级伙伴，为复合性提供了一个新的窗口。我们表明，顶级合作伙伴射流可以有效地解决在某些地区的参数空间。这种“加强的顶级合伙人”的签名值得开发专门的子结构分析。
We study a holographic realisation of a composite Higgs model with an SO(6)/SO(5) symmetry breaking coset in which the top sector includes colour-neutral twin-partners that reduce the sensitivity of the Higgs mass to the cut-off. Key to this neutral-naturalness mechanism is a Z2 symmetry that leaves the Yukawa couplings to the Higgs boson invariant under an exchange of the top quark and twin top quark, but the symmetry structure of the model means that the Z2 symmetry is not present in the gauge boson couplings to the Higgs. Within the calculable framework of holography we construct and study …
We calculate loop induced lepton flavor violating Higgs decays in the Littlest Higgs model with T-parity. We find that a finite amplitude is obtained only when all contributions from the T-odd lepton sector are included. This is in contrast to lepton flavor violating processes mediated by gauge bosons where the partners of the right-handed mirror leptons can be decoupled from the spectrum. These partners are necessary to cancel the divergence in the Higgs mass introduced by the mirror leptons but are otherwise unnecessary and assumed to be decoupled in previous phenomenological studies. Furthe…
We build a minimal neutral naturalness model in which the top partners are not charged under QCD, with a pseudo Goldstone Higgs arising from $SO(5)/SO(4)$ breaking. The color-neutral top partners generate the Higgs potential radiatively without quadratic divergence. The misalignment between the electroweak scale and global symmetry breaking scale is naturally obtained from suppression of the Higgs quadratic term, due to cancellation between singlet and doublet top partner contributions. This model can be embedded into ultraviolet holographic setup in composite Higgs framework, which even reali…
The single vector-like top partner hadroproduction in association with top quark in the five and the six-flavour schemes at the LHC is investigated. The inclusive cross section and the differential distributions are evaluated for many benchmark scenarios at leading and next-to-leading orders, both for fixed-order and fixed-order matched to parton shower. The associated Higgs production with a top quark pair, where the final state arises from the decay of the vector-like top partner into a Higgs boson and a top quark, is examined.
