scholarly journals A more natural composite Higgs model

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Hsin-Chia Cheng ◽  
Yi Chung
Keyword(s):  
Standard Model ◽  
Higgs Model ◽  
Quadratic Term ◽  
Beyond The Standard Model ◽  
Higgs Potential ◽  
Little Higgs ◽  
Composite Higgs ◽  
Partial Compositeness ◽  
Quartic Term ◽  
Natural Composite

Abstract Composite Higgs models provide an attractive solution to the hierarchy problem. However, many realistic models suffer from tuning problems in the Higgs potential. There are often large contributions from the UV dynamics of the composite resonances to the Higgs potential, and tuning between the quadratic term and the quartic term is required to separate the electroweak breaking scale and the compositeness scale. We consider a composite Higgs model based on the SU(6)/Sp(6) coset, where an enhanced symmetry on the fermion resonances can minimize the Higgs quadratic term. Moreover, a Higgs quartic term from the collective symmetry breaking of the little Higgs mechanism can be realized by the partial compositeness couplings between elementary Standard Model fermions and the composite operators, without introducing new elementary fields beyond the Standard Model and the composite sector. The model contains two Higgs doublets, as well as several additional pseudo-Nambu-Goldstone bosons. To avoid tuning, the extra Higgs bosons are expected to be relatively light and may be probed in the future LHC runs. The deviations of the Higgs couplings and the weak gauge boson couplings also provide important tests as they are expected to be close to the current limits in this model.

scholarly journals Electroweak phase transition triggered by fermion sector

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Qing-Hong Cao ◽  
Katsuya Hashino ◽  
Xu-Xiang Li ◽  
Zhe Ren ◽  
Jiang-Hao Yu
Keyword(s):  
Phase Transition ◽  
Quadratic Term ◽  
Mass Hierarchy ◽  
Higgs Potential ◽  
Electroweak Phase Transition ◽  
First Order ◽  
First Order Phase Transition ◽  
Higher Dimensional ◽  
Quartic Term ◽  
First Order Phase

Abstract To realize first-order electroweak phase transition, it is necessary to generate a barrier in the thermal Higgs potential, which is usually triggered by scalar degree of freedom. We instead investigate phase transition patterns in pure fermion extensions of the standard model, and find that additional fermions with mass hierarchy and mixing could develop such a barrier and realize a strongly first-order phase transition in such models. In the Higgs potential with polynomial parametrization, the barrier can be generated in the following two patterns by fermionic reduction effects: (I) positive quadratic term, negative cubic term and positive quartic term or (II) positive quadratic term, negative quartic term and positive higher dimensional term, such as dimensional 6 operator.

scholarly journals THE LEPTON FLAVOR VIOLATING DECAYS Z→li lj IN THE SIMPLEST LITTLE HIGGS MODEL

2012 ◽  
Vol 27 (28) ◽  
pp. 1250158 ◽  
Author(s):  
XIAO-FANG HAN ◽  
LEI WANG
Keyword(s):  
Standard Model ◽  
Z Boson ◽  
Branching Ratios ◽  
Higgs Model ◽  
Little Higgs ◽  
Decay Modes ◽  
Lepton Flavor ◽  
Loop Level ◽  
Flavor Changing ◽  
The Standard Model

In the simplest little Higgs model the new flavor-changing interactions between heavy neutrinos and the Standard Model leptons can generate contributions to some lepton flavor violating decays of Z-boson at one-loop level, such as Z→τ±μ∓, Z→τ±e∓ and Z→μ±e∓. We examine the decay modes and find that the branching ratios can reach 10-7 for the three decays, which should be accessible at the GigaZ option of the ILC.

scholarly journals A NEW MECHANISM FOR NEUTRINO MASS

1999 ◽  
Vol 14 (14) ◽  
pp. 913-917 ◽  
Author(s):  
P. P. DIVAKARAN ◽  
G. RAJASEKARAN
Keyword(s):  
Standard Model ◽  
Neutrino Mass ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Composite Higgs ◽  
The Standard Model

A mechanism for generating massive but naturally light Dirac neutrinos is proposed. It involves composite Higgs within the standard model as well as some new interaction beyond the standard model. According to this scenario, a neutrino mass of 0.1 eV or higher, signals new physics at energies of 10–100 TeV or lower.

scholarly journals Double Protection of the Higgs Potential in a Supersymmetric Little Higgs Model

2006 ◽  
Vol 96 (3) ◽  
Author(s):  
Zurab Berezhiani ◽  
Piotr H. Chankowski ◽  
Adam Falkowski ◽  
Stefan Pokorski
Keyword(s):  
Higgs Model ◽  
Higgs Potential ◽  
Little Higgs

Beyond the Standard Model

2017 ◽  
Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Supergravity Models ◽  
Standard Model ◽  
Field Theories ◽  
Beyond The Standard Model ◽  
Super Symmetry ◽  
The Standard Model ◽  
Topological Field ◽  
Supersymmetric Theories

The motivation for supersymmetry. The algebra, the superspace, and the representations. Field theory models and the non-renormalisation theorems. Spontaneous and explicit breaking of super-symmetry. The generalisation of the Montonen–Olive duality conjecture in supersymmetric theories. The remarkable properties of extended supersymmetric theories. A brief discussion of twisted supersymmetry in connection with topological field theories. Attempts to build a supersymmetric extention of the standard model and its experimental consequences. The property of gauge supersymmetry to include general relativity and the supergravity models.

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