相关论文: Extra doublets - Global analyses of Standard Model…
We study the most general scalar potential of the Georgi-Machacek model, which adds isospin-triplet scalars to the Standard Model (SM) in a way that preserves custodial SU(2) symmetry. We show that this model possesses a decoupling limit,…
The global fit of the Standard Model to electroweak precision data, routinely performed by the LEP electroweak working groups and others, has been revisited in view of (i) the development of the new generic fitting package, Gfitter, (ii)…
We describe a simple extension of the standard model, containing a scalar singlet and a triplet fermion. The model can explain the possible enhancement in the decay $H \rightarrow \gamma \gamma$ at the LHC together with the excess found in…
We study a fermionic dark matter model in which the interaction of the dark and visible sectors is mediated by Higgs portal type couplings. Specifically, we consider the mixing of a dark sector scalar with the scalars of a Two Higgs Doublet…
The charged fermion mass matrices are always invariant under $U(1)^3$ symmetry linked to the fermion number transformation. A class of two Higgs doublet models (2HDM) can be identified by requiring that the definition of this symmetry in an…
We consider the conditions for the validity of a two-Higgs doublet model at high energy scales, together with all other low- and high-energy constraints. The constraints on the parameter space at low energy, including the measured value of…
The analysis of the Higgs boson data by the ATLAS and CMS Collaborations appears to exhibit an excess of h --> gamma\gamma events above the Standard Model (SM) expectations; whereas no significant excess is observed in h --> ZZ* --> {four…
Recent reports from the Large Hadron Collider indicate two excesses: one in the lighter Higgs mass region around 95 GeV, and another in the rare $Z \gamma$ final state of the Standard Model (SM) 125 GeV Higgs decay. These anomalies are…
After operations at the LHC and e^+e^- Linear Colliders it may be found that a Standard-Model-like scenario is realized. In this scenario no new particle will be discovered, except a single Higgs boson having partial widths or coupling…
We discuss a minimal extension to the standard model in which there are two Higgs bosons and, in addition to the usual fermion content, two fermion doublets and one fermion singlet. The little hierachy problem is solved by the vanishing of…
The Two Higgs Doublet model and its phenomenological implications are discussed. A brief survey on the present status of this model is given. In particular, we concentrate on the Two Higgs Doublet Model with Flavor Changing Neutral…
The main result of this paper is a collection of conservative naturalness bounds on minimal extensions of the standard model by (vector-like) fermionic or scalar gauge multiplets. Within, we advocate for an intuitive and physical concept of…
The Lee-Wick Standard Model is a highly constrained model which solves the gauge hierarchy problem at the expense of including states with negative norm. It appears to be macroscopically causal and consistent. This model is extended by…
With the assumption of classical scale invariance at the Planck scale, the DFSZ axion model can generate the Higgs mass terms of the appropriate size through technically natural parameters and may be valid up to the Planck scale. We discuss…
In this article we investigate a conformal extension of the standard model in which the scalar sector consists of a standard model Higgs doublet, a real gauge singlet and a real $SU(2)_{L}$ triplet. Focusing on the scenario where the Higgs…
Recently, the CDF collaboration has reported a new precision measurement of the $W$-boson mass, $M_W$, showing a large deviation from the value predicted by the Standard Model (SM). In this paper, we analyse possible new physics…
We present an update of the Standard Model fit to electroweak precision data. We include newest experimental results on the top quark mass, the W mass and width, and the Higgs boson mass bounds from LEP, Tevatron and the LHC. We also…
The simplest extension of the Standard Model is to add a gauge singlet scalar, $S$: the singlet extended Standard Model. In the absence of a $Z_2$ symmetry $S\rightarrow -S$ and if the new scalar is sufficiently heavy, this model can lead…
We discuss the classification of symmetries and the corresponding symmetry groups in the two-Higgs-doublet model (THDM). We give an easily useable method how to determine the symmetry class and corresponding symmetry group of a given THDM…
We derive the complete set of continuous maximal symmetries for Standard Model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs Doublet Models, with $n > 2$ Higgs doublets. Our results generalize the…