Simplest Little Higgs Model Research Articles

Anomalous magnetic and weak magnetic dipole moments of the tau lepton in the simplest little Higgs model

We obtain analytical expressions, both in terms of parametric integrals and Passarino–Veltman scalar functions, for the one-loop contributions to the anomalous weak magnetic dipole moment (AWMDM) of a charged lepton in the framework of the simplest little Higgs model (SLHM). Our results are general and can be useful to compute the weak properties of a charged lepton in other extensions of the standard model (SM). As a by-product we obtain generic contributions to the anomalous magnetic dipole moment (AMDM), which agree with previous results. We then study numerically the potential contributions from this model to the tau lepton AMDM and AWMDM for values of the parameter space consistent with current experimental data. It is found that they depend mainly on the energy scale f at which the global symmetry is broken and the t_{beta } parameter, whereas there is little sensitivity to a mild change in the values of other parameters of the model. While the tau AMDM is of the order of 10^{-9}, the real (imaginary) part of its AWMDM is of the order of 10^{-9} (10^{-10}). These values seem to be out of the reach of the expected experimental sensitivity of future experiments.

Dipole moments of the tau-neutrino from the process [formula omitted

In the framework of a Simplest Little Higgs Model (SLHM), we calculate the total cross section for the reaction e+e−→νν¯γ and thereafter we get a limit on the characteristic energy scale of the model f, f≥5.5TeV, which in turn induces bounds on the anomalous Magnetic Moment (MM) and the Electric Dipole Moment (EDM) of the tau-neutrino. We consider initial-state radiation, and neglect W and photon exchange diagrams. The results are based on the data reported by the L3 Collaboration at LEP, and compare favorably with the limits obtained in other models, complementing previous studies on the dipole moments.

Discrimination of the lightCP-odd scalars in the NMSSM and in the simplest little Higgs model

The presence of the light CP-odd scalar boson predicted in the next-to-minimal supersymmetric model (NMSSM) and the simplest little Higgs model (SLHM) dramatically changes the phenomenology of the Higgs sector. We suggest a practical strategy to discriminate the underlying model of the CP-odd scalar boson produced in the decay of the standard model-like Higgs boson. We define the decay rate of "the non $b$-tagged jet pair" with which we compute the ratio of decay rates into lepton and jets. They show much different behaviors between the NMSSM and the SLHM.

ASSOCIATED PRODUCTION OF LIGHT PSEUDOSCALAR BOSON η WITH TOP QUARK PAIRS IN THE SLH MODEL AT THE ILC

The light pseudoscalar boson η is the typical particle predicted by the Simplest Little Higgs (SLH) model. In this paper, we investigate some processes of the associated production of a light pseudoscalar boson η with a pair of top quarks in the SLH model at the International Linear Collider (ILC), i.e. [Formula: see text] and [Formula: see text]. We find that the cross-sections of these two processes could reach [Formula: see text] fb in the favorite parameter space in the SLH model, which is consistent with the results of the cross-section of [Formula: see text] in the standard model and the cross-section of [Formula: see text] in the minimal supersymmetric standard model. It should be clear that hundreds to thousands of η can be produced at the ILC per year, these processes of [Formula: see text] are really interesting in testing the standard model and searching the signs of the SLH model.

Pseudoscalar boson and standard model-like Higgs boson productions at the LHC in the simplest little Higgs model

In the framework of the simplest little Higgs model (SLHM), we perform a comprehensive study for the pair productions of the pseudoscalar boson {\eta} and SM-like Higgs boson h at LHC, namely gg(b\bar{b})-> {\eta}{\eta}, gg(q\bar{q})-> {\eta}h and gg(b\bar{b})-> hh. These production processes provide a way to probe the couplings between Higgs bosons. We find that the cross section of gg-> {\eta}{\eta} always dominates over that of b\bar{b}-> {\eta}{\eta}. When the Higgs boson h which mediates these two processes is on-shell, their cross sections can reach several thousand $fb$ and several hundred $fb$, respectively. When the intermediate state h is off-shell, those two cross sections are reduced by two orders of magnitude, respectively. The cross sections of gg-> {\eta}h and q\bar{q}-> {\eta}h are about in the same order of magnitude, which can reach $\ord{(10^2fb)}$ for a light {\eta} boson. Besides, compared with the SM prediction, the cross section of a pair of SM-like Higgs bosons production at LHC can be enhanced sizably. Finally, we briefly discuss the observable signatures of {\eta}{\eta}, {\eta}h and hh at the LHC, respectively.

BOUNDING THE ELECTROMAGNETIC AND WEAK DIPOLE MOMENTS OF THE TAU–LEPTON IN A SIMPLEST LITTLE HIGGS MODEL

From the total cross-section for the reaction e+e-→τ+τ-γ at the Z1 pole and in the framework of a simplest little Higgs model (SLHM), we get a limit on the characteristic energy scale of the model f, f ≥ 5.4 TeV , which in turn induces bounds on the electromagnetic and weak dipole moments of the tau–lepton. Our bounds on the electromagnetic moments are consistent with the bounds obtained by the L3 and OPAL collaborations for the reaction e+e-→τ+τ-γ. We also obtained bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI and ALEPH collaborations from the reaction e+e-→τ+τ-.

Higgs-pair production and decay in simplest little Higgs model

In the framework of the simplest little Higgs model (SLHM), we study the production of a pair of neutral CP-even Higgs bosons at the LHC. First, we examine the production rate and find that it can be significantly larger than the SM prediction. Then we investigate the decays of the Higgs-pair and find that for a low Higgs mass their dominant decay mode is h h → η η η η ( η is a CP-odd scalar) while h h → b b ¯ η η and h h → η η W W may also have sizable ratios. Finally, we comparatively study the rates of p p → h h → b b ¯ τ + τ − , p p → h h → b b ¯ γ γ , and p p → h h → W W W W in the SLHM and the littlest Higgs models (LHT). We find that for a light Higgs, compared with the SM predictions, all the three rates can be sizably enhanced in the LHT but severely suppressed in the SLHM; while for an intermediately heavy Higgs, both the LHT and SLHM can enhance sizably the SM predictions.