相关论文: Upper Bound on R_b in Two Higgs Doublet Model from…
We study constraints on type-II two Higgs doublet models at large tan{beta} from LEP/SLD Z-pole data and from lepton universality violation in W decay. We perform a global fit and find that, in the context of Z decay, the LEP/SLD…
The present upper bound on $\kappa_e$, the ratio between the electron Yukawa coupling and its Standard Model value, is of ${\cal O}(600)$. We ask what would be the implications in case that $\kappa_e$ is close to this upper bound. The…
With no New Physics seen at the LHC, a second Higgs doublet remains attractive and plausible. The ratio ${\cal R}_B^{\mu/\tau} = {\cal B}(B \to \mu \bar\nu)/{\cal B}(B \to \tau \bar\nu)$ is predicted at 0.0045 in both the Standard Model and…
We perform a combined analysis of two stringent constraints on two Higgs doublet model, coming from the recently announced CLEO II bound on $B(b \rightarrow s \gamma)$ and $Z \rightarrow b \overline b$ and from the recent LEP data on the…
Recent progress on muon $g-2$ measurement prompts one to take it even more seriously. In the general two Higgs doublet model that allows extra Yukawa couplings, we take a simplified approach of single enhanced coupling. We fix the charged…
Nowadays in the MSSM the moderate values of $\tan\beta$ are almost excluded by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal Supersymmetric Standard Model the theoretical upper bound on it increases and reaches…
There exist about $3.7\sigma$ positive and $2.4\sigma$ negative deviations in the muon and electron anomalous magnetic moments ($g-2$). Also, some ratios for lepton universality in $\tau$ decays have almost $2\sigma$ deviations from the…
We discuss the impact of the recent precision measurements at LEP on the minimal supersymmetric standard model. We show that the values of $\tan\beta$ necessary to induce large positive corrections to $R_b$ are the same as the ones…
Using the experimental data on meson decay rates, mixing and CP violation we set competitive upper and lower limits to the parameter tan(beta) as a function of the mass of the charged Higgs m_H in the Two Higgs Doublet Model (Model II).
We examine the level of enhancement that can be achieved in the ZZ and \gamma\gamma channels for a two-Higgs-doublet model Higgs boson (either the light h or the heavy H) with mass near 125 GeV after imposing all constraints from LEP data,…
Imposing the theoretical constraints from vacuum stability, unitarity and perturbativity as well as the experimental constraints from the electroweak precision data, flavor observables and the non-observation of additional Higgs at…
The upper bound on the mass of the lightest Higgs boson is provided in the supersymmetric standard model with multi-Higgs doublets, up to two-loop order. Relatively large corrections are expected from the experimentally unconstrained extra…
We present analytic expressions for the top and bottom Yukawa couplings in the context of the minimal supersymmetric standard model when both couplings $h_{t,0},h_{b,0}$ are large at the unification scale. For sufficiently large…
Allowing for realistic uncertainties in input parameters, we demonstrate that the present CLEO limit of $5.4\times 10^{-4}$ for inclusive $b\to s\gamma$ decay does not yet fully exclude the $t\to bH^+$ decay possibility in supersymmetric…
A recent analysis of the LEP data shows an interesting deviation from lepton universality in W boson decays. An excess at the level of 2.8 sigma is found in the tau mode branching ratio with respect to the other two modes. It is suggested…
We show that in a two Higgs doublet model type-II extended by vectorlike leptons the contributions from heavy neutral and charged Higgs bosons to the anomalous magnetic moment of the muon simultaneously feature chiral enhancement from…
The two Higgs doublet model emerges as a minimal scenario in which to address, at the same time, the $\gamma\gamma$ excess at 750 GeV and the lepton flavour violating decay into $\tau^\pm \mu^\mp $ of the 125 GeV Higgs boson. The price to…
In two-Higgs-doublet models with exact $Z_2$ symmetry, putting $m_h \simeq 125$ GeV at the alignment limit, the following limits on the heavy scalar masses are obtained from the conditions of unitarity and stability of the scalar potential:…
We present new upper limits on the light Higgs boson mass mh in supersymmetric models. We consider two gravity-mediated models (with and without universal scalar masses) and two gauge-mediated models (with a 5+5 or 10+10 messenger sector).…
We study low-energy consequences of supersymmetric $SO(10)$ models with Yukawa unification $h_t = h_N$ and $h_b = h_\tau$. We find that it is difficult to reproduce the observed $m_b/m_\tau$ ratio when the third-generation right-handed…