7 pages, 2 figures, To appear in the proceedings of 2009 Nagoya Global COE Workshop, Strong Coupling Gauge Theories in LHC era (SCGT09), December 8-11 2009, Nagoya, Japan
Higgs boson production by the gluon fusion and its decay into two photons at the LHC are investigated in the context of the gauge-Higgs unification scenario. The qualitative behaviors for these processes in the scenario are quite distinguishable from those of the Standard Model and the universal extra dimension scenario because of the overall sign difference for the effective couplings induced by one-loop corrections through Kaluza-Klein modes.
We discuss renormalization group equations for gauge coupling constants in gauge-Higgs grand unification on five-dimensional Randall-Sundrum warped space. We show that all the four-dimensional Standard Model gauge coupling constants are asymptotically free and are effectively unified in $SO(11)$ gauge-Higgs grand unified theories on 5D Randall-Sundrum warped space.
We consider the triple coupling of the Higgs boson in the context of the gauge-Higgs unification scenario. We show that the triple coupling of the Higgs boson in this scenario generically deviates from SM prediction since the Higgs potential in this scenario has a periodicity. We calculate the coupling in the five-dimensional $SU(3)$ x $U(1)_X$ gauge-Higgs unification model and obtain 70% deviation from the SM prediction.
Gauge coupling unification is studied within the framework where there are extra Higgs doublets and $E_6$ exotic fields. Supersymmetric models and nonsupersymmetric models are investigated, and a catalog of models with gauge coupling unification is presented.
The Higgs boson is unified with gauge fields in the gauge-Higgs unification. The $SO(5) \times U(1)$ gauge-Higgs electroweak unification in the Randall-Sundrum warped space yields almost the same phenomenology at low energies as the standard model, and gives many predictions for the Higgs couplings and new $W', Z'$ bosons around $6 \sim 8$ TeV, which can be tested at 14 TeV LHC. The gauge-Higgs grand unification is achieved in $SO(11)$ gauge theory. It suggests the existence of the sixth dimension (GUT dimension) in addition to the fifth dimension (electroweak dimension). The proton decay is n…
The effective Higgs theories at the TeV scale in supersymmetric $SU(5)$ grand unification models are systematically derived. Restricted to extensions on $\mathbf{5}_{H}$ containing the Higgs sector we show that only two types of real (vector-like) models and one type of chiral model are found to be consistent with perturbative grand unification. While the chiral model has been excluded by the LHC data, the fate of perturbative unification will be uniquely determined by the two classes of vector-like models.
We discuss the Yukawa coupling unification, a very interesting prediction of the grand unified theory, in the context of scenarios with more than one pair of Higgs doublet since the current LHC constraint has become a problem for the Yukawa unification scenarios with just one pair of Higgs doublet. More than one pair of Higgs doublets can easily arise in missing partner mechanism which solves the doublet-triplet splitting problem. In such a scenario, the Yukawa unification occurs at a medium $\tanβ$ value, e.g., $\sim$ 30, which corresponds to much smaller threshold corrections compared to usu…
We analyze the structure of the Higgs potential in gauge-Higgs unification with a flat extra dimension. As a concrete model, we first consider the cases where the Standard Model Higgs doublet is embedded into a higher-dimensional $SU(3)_{w}^{}$ gauge multiplet with five-dimensional Lorentz symmetry relaxed. In this $SU(3)_{w}^{}$ model with Lorentz violation, the deviation of the resulting triple Higgs boson coupling from its SM prediction is shown to be less than $10\%$ when the compactification scale is larger than the experimental lower bound, which is around 5 TeV. Next, we examine the Hig…
4D Higgs field is identified with the extra-dimensional component of gauge potentials in the gauge-Higgs unification scenario. $SO(5) \times U(1)$ gauge-Higgs EW unification in the Randall-Sundrum warped space is successful at low energies. The Higgs field appears as an Aharonov-Bohm phase $θ_H$ in the fifth dimension. Its mass is generated at the quantum level and is finite. The model yields almost the same phenomenology as the standard model for $θ_H < 0.1$, and predicts $Z'$ bosons around 6 - 10 TeV with very broad widths. The scenario is genelarized to $SO(11)$ gauge-Higgs grand unificatio…
In this paper, we discuss the UV sensitivity of the Higgs effective potential in a Gauge-Higgs Unification (GHU) model. We consider an $SU(\mathcal N)$ GHU on $\mathbf M^4\times S^1$ spacetime with a massless Dirac fermion. In this model, we evaluate the four-Fermi diagrams at the two-loop level and find them to be logarithmically divergent in the dimensional regularization scheme. Moreover, we confirm that their counter terms contribute to the Higgs effective potential at the four-loop level. This result means that the Higgs effective potential in the GHU depends on UV theories as well as in …
We propose a new model of 5D $SU(3)\otimes U(1)_X$ gauge-Higgs unification with a successful electroweak symmetry breaking and a realistic Higgs boson mass. In our model, the representations of the fermions are very simple, the ${\bf 3}, \overline{\bf 3}$ and $\bf \overline{15}$ representations of $SU(3)$ gauge group. Employing the anti-periodic boundary conditions for $\bf \overline{15}$ reduces massless exotic fermions and simplifies the brane localized mass terms. We calculate the 1-loop Higgs potential in detail and find that a realistic electroweak symmetry breaking and the observed Higgs…
We explore $t-b-τ$ Yukawa unification (YU) in a supersymmetric $SU(4)_c \times SU(2)_L \times SU(2)_R $ model without imposing a discrete left-right (L-R) symmetry. A number of interesting solutions that are compatible with $t-b-τ$ YU, LSP neutralino dark matter (DM), and LHC and other experimental constraints are identified. In particular, they include gluino-neutralino and stau-neutralino co-annihilation scenarios, where the NLSP gluino mass can range from 1-3 TeV. Higgsino-like dark matter solutions are also identified for which gluino masses can approach 5 TeV or so. This scenario will be …
In this paper, we investigate the finiteness of the Higgs effective potential in an ${\rm SU}(\mathcal N)$ Gauge-Higgs Unification (GHU) model defined on ${\bf M}^4\times S^1$. We obtain the Higgs effective potential at the two-loop level and find that it is finite. We also discuss that the Higgs effective potential is generically divergent for three- or higher-loop levels. As an example, we consider an ${\rm SU}(\mathcal N)$ gauge theory on ${\bf M}^5\times S^1$, where the one-loop corrections to the four-Fermi operators are divergent. We find that the Higgs effective potential depends on the…
$SO(5) \times U(1) \times SU(3)$ gauge-Higgs unification model inspired by $SO(11)$ gauge-Higgs grand unification is constructed in the Randall-Sundrum warped space. The 4D Higgs boson is identified with the Aharonov-Bohm phase in the fifth dimension. Fermion multiplets are introduced in the bulk in the spinor, vector and singlet representations of $SO(5)$ such that they are implemented in the spinor and vector representations of $SO(11)$. The mass spectrum of quarks and leptons in three generations is reproduced except for the down quark mass. The small neutrino masses are explained by the ga…
We examine trilinear gauge boson couplings (TGCs) in the context of the $SU(3)_W\otimes U(1)'$ gauge-Higgs unification scenario. The TGCs play important roles in the probes of the physics beyond the standard model, since they are highly restricted by the experiments. We discuss mass spectrum of the neutral gauge boson with brane-localized mass terms carefully and find that the TGCs and $ρ$ parameter may deviate from standard model predictions. Finally we put a constraint from these observables and discuss the possible parameter space.
We explore gauge coupling unification and dark matter in high scale supersymmetry where the scale of supersymmetry breaking is much above the weak scale. The gauge couplings unify as precisely as in low energy supersymmetry if the higgsinos, whose mass does not break supersymmetry, are much lighter than those obtaining masses from supersymmetry breaking. The dark matter of the universe can then be explained by the neutral higgsino or the gravitino. High scale supersymmetry with light higgsinos requires a large Higgs mixing parameter for electroweak symmetry breaking to take place. It is thus n…
The Decay b -> s gamma, the Higgs Boson Mass, and Yukawa Unification without R-Parity
我们回顾了双线性R-宇称破坏模型的一些性质：由R-宇称自发破缺引起的最小超对称标准模型的简单扩展。我们集中在B（b -> s γ）的测量所施加的荷电希格斯质量上的边界的松弛，对最轻的中性希格斯玻色子玻色子的质量的影响，电弱对称性的辐射破缺，底部和Tau Yukawa耦合的统一，以及这些现象与辐射产生的Tau中微子质量的关系。
