Related papers: Little-Higgs corrections to precision data after L…
We investigate the phenomenological implications of a light scalar bottom quark, with a mass of about the bottom quark mass, within the minimal supersymmetric standard model. The study of such a scenario is of theoretical interest, since,…
We update the constraints on two-Higgs-doublet models (2HDMs) focusing on the parameter space relevant to explain the present muon $g$$-$$2$ anomaly, $\Delta a_{\mu}$, in four different types of models, type I, II, "lepton specific" (or X)…
We study a two-Higgs doublet model extended with an additional singlet scalar (2HDM+S), and provide a brief introduction to the model and its parameters. Constraints are applied to the parameter space of this model in order to accommodate a…
The measurements performed at LEP and SLC have substantially improved the precision of the test of the Minimal Standard Model. The precision is such that there is sensitivity to pure weak radiative corrections. This allows to indirectly…
It is possible to place direct constraints on WW-photon and WWZ couplings by studying their tree-level contributions to the process e^+e^- ---> W^+W^-. However, these couplings also contribute at the loop level to e^+e^- ---> f fbar…
We present an up-to-date analysis of the constraints imposed bythe precision data on the ($CP-$ conserving) Two-Higgs-Doublet Model of type II, with emphasis on the possible existence of very light neutral (pseudo)scalar Higgs boson with…
We have calculated the cross section of the process e^+e^- \to \gamma\gamma \to b\bar{b} in the littlest Higgs model with T parity (LHT). We find that, for the favorable parameters, the total cross section \sigma(e^+e^- \to \gamma\gamma \to…
We have examined the evidence for the electroweak radiative corrections in the LEP precision data sets of 1993 and 1994 along with the intriguing possibility that the QED corrections only may be sufficient to fit the data within the…
In light of the discovery of a Higgs-like particle at the LHC, we revisit the status of the precision electroweak data, focusing on two discrepant observables: 1) the long-standing 2.4 sigma deviation in the forward-backward asymmetry of…
The current experimental lower bound on the Higgs mass significantly restricts the allowed parameter space in most realistic supersymmetric models, with the consequence that these models exhibit significant fine-tuning. We propose a…
The predicted value of the higgs mass $m_H$ is analyzed assuming the existence of the fourth generation of leptons ($N, E$) and quarks ($U, D$). The steep and flat directions are found in the five-dimensional parameter space: $m_H$, $m_U$,…
The status of published and preliminary precision electroweak measurements as of winter 2002/03 is presented. The new results on the mass of the W boson as measured at LEP-2 and on atomic parity violation in Caesium are included. The…
We have examined the electroweak radiative corrections in the LEP precision data in view of the new measurements of $M_W$ and $m_t$ as well as the recent progress in the higher order radiative corrections. From the minimal $\chi^2$-fit to…
We present the details of a global $\chi^2$ analysis of electroweak data, including fermion masses and mixing angles, in SO(10) SUSY GUTs. Just as precision electroweak data is used to test the Standard Model, the well determined Standard…
In the context of the littlest Higgs$(LH)$ model, we study the process $ e^{+}e^{-}\to t\bar{t}$. We find that the new gauge bosons $Z_{H}$ and $B_{H}$ can produce significant correction effects on this process, which can be further…
With an eye toward the precision physics of the LHC, such as the recent measurement of $M_W$ by the ATLAS Collaboration, we present here systematic studies relevant to the assessment of the expected size of multiple photon radiative effects…
We study the general Zee model, which includes an extra Higgs scalar doublet and a new singly-charged scalar singlet. Neutrino masses are generated at one-loop level, and in order to describe leptonic mixing, both the Standard Model and the…
The interpretation of electroweak precision data in the Standard Model Effective Field Theory is discussed. One loop corrections $\propto y_t^2, \lambda$ to the partial $Z$ decay widths and ratios of partial widths in this theory are…
We will study some possible non universal corrections that could affect single measurements of the Weinberg angle sin^2(theta) (leaving the full average essentially unchanged). We will concentrate on the class of the models that introduces…
In the presence of the T-parity violating Wess-Zumino-Witten (WZW) anomaly term, the otherwise stable heavy photon A_H in the Littlest Higgs model with T-parity (LHT) decays to either Standard Model (SM) gauge boson pairs, or to SM fermions…