相关论文: Bounds on the New Generations

An alternative to the idea of a metastable electroweak vacuum would be an initial restriction to the pure scalar sector of the Standard Model, but describing spontaneous symmetry breaking consistently with studies indicating that there are…

Vacuum stability implies a lower limit on the mass of the higgs boson in the Standard Model (SM). In contrast, an upper limit on the lightest higgs mass can be calculated in supersymmetric (susy) models. The main uncertainty in each limit…

We take the standard model to be an effective theory including higher dimensional operators suppressed by scale $\Lambda$ and re-examine the higgs mass bounds from the requirements of vacuum stability. Our results show that the effects of…

We consider a hypothetical scenario in which the Higgs boson is absent, and attempt to constrain the mass scale Lambda of the new physics that would take its place. Using recent measurements of sin^2(theta_eff^lept) and M_W, we show that,…

Theoretical implications of the possible observation of a Higgs boson with a mass of about 115 GeV at LEP are discussed. Within the Standard Model a Higgs boson in this mass range agrees well with the indirect constraints from electroweak…

Recently the ATLAS and CMS collaborations presented preliminary results of Standard Model Higgs searches and reported excesses of events for a Higgs boson at 124-126 GeV. Such a Higgs mass can be naturally realized, simultaneously…

If next generations of heavy quarks and leptons exist within the standard model (SM), they can manifest themselves in Higgs boson production at the Tevatron and the LHC, before being actually observed. This generation leads to an increase…

We discuss the bound on the mass of the Higgs boson arising from precision electroweak measurements in the context of the triviality of the scalar Higgs model. We show that, including possible effects from the underlying nontrivial…

The possibility that the Standard Model (SM) is valid up to the Planck scale $M_P$, i.e. that new physics occurs only around $M_P$, is nowadays largely explored. For a metastable EW vacuum, we show that new physics interactions can have a…

We derive the low-energy electroweak effective lagrangian for the case of additional heavy, unmixed, sequential fermions. Present data still allow for the presence of a new quark and/or lepton doublet with masses greater than $M_Z/2$,…

In the present paper we argue that the correction to the Higgs mass coming from the bound state of 6 top and 6 anti-top quarks, predicted early by C.D. Froggatt and ourselves, leads to the Standard Model vacuum stability and confirms the…

We have studied imposing the condition that the Standard Model effective Higgs potential should have two approximately degenerate vacua, such that the vacuum we live in is just barely metastable: the one in which we live has a vacuum…

Theoretical arguments and lattice simulations suggest that, beside the known resonance of mass $m_h=$ 125 GeV, the Higgs field might exhibit a second resonance with a larger mass $(M_H)^{\rm theor} = 690 \pm 10 ~({\rm stat}) \pm 20 ~({\rm…

From non-observation at LEP1, a lower mass limit of 45 GeV has been established on any additional sequential fermion beyond the three generations. Precision measurements have further constrained the number of such additional generations,…

The latest results of Higgs boson searches from the four LEP experiments, ALEPH, DELPHI, L3 and OPAL, are reviewed using the data taken in 1996 at center-of-mass energies between 161 and 172 GeV. No signal was observed. The 95% CL combined…

Experimental and theoretical clues both suggest that the Higgs boson has a mass below the LEP2 lower limit of 114.4 GeV. If true, this suggests that the dominant Higgs decay is nonstandard while the production cross sections remain…

We examine various direct and indirect constraints on the lepton-specific two-Higgs doublet model and scrutinize the property of the Higgs bosons in the allowed parameter space. These constraints come from the precision electroweak data,…

Limits are derived on models with extended Higgs sectors, including the Minimal Supersymmetric Standard Model (MSSM), by exploiting the data on $\tau^+ \tau^- + $ 2 jets final states, used by the CDF collaboration to place limits on third…

We re-examine our former predictions \cite{kahanath1,kahanath2} of the top and Higgs masses via dynamical symmetry breaking in a 4-fermion theory which produces the Higgs as a bound state, and relates the top and Higgs masses to $m_W$. The…

We update our previous analysis on the Higgs mass $m_h$ and the QCD coupling $\alpha_s(=\alpha_s(M_z))$ by using the LEP data after the 1995 Winter Conferences. For $m_t=180$ GeV we find evidence for a rather large value of the Higgs mass…