Related papers: Improved Constraints on Z' Bosons from Electroweak…
A new general parameterization with eight mixing parameters among Z, gamma and an extra neutral gauge boson Z' is proposed and subjected to phenomenological analysis. We show that in addition to the conventional Weinberg angle theta_W,…
The study of electron-positron collisions at LEP, together with additional measurements from other experiments, in particular those at SLC and at the Tevatron, has allowed for tests of the electroweak Standard Model with unprecedented…
The current status of electroweak physics results from LEP is reviewed. Particular emphasis is placed on the latest results on the properties of the Z and W bosons. The updated status of the global electroweak fit to the standard model and…
We obtain bounds for the mass of the extra neutral gauge boson, ${Z^\prime}$, predicted by two versions of ${SU (3)_C \times SU (3)_L \times U (1)_X}$ model, namely one corresponding to its minimal version and another where the neutrinos…
We study precision electroweak constraints on the close cousin of the Littlest Higgs, the SU(6)/Sp(6) model. We identify a near-oblique limit in which the heavy W' and B' decouple from the light fermions, and then calculate oblique…
Results of an updated global electoweak fit to the Standard Model (SM) are presented, where special attention is paid to some key observables, such as the weak mixing angle, the $W$ boson mass, and the anomalous magnetic moment of the muon.…
Recent developments in the measurement of precision electroweak measurements are summarised, notably new results on the mass of the top quark and mass and width of the W boson. Predictions of the Standard Model are compared to the…
We study the constraints that electroweak precision data can impose, after the discovery of the Higgs boson by the LHC, on neutrinophilic two-Higgs-doublet models which comprise one extra $SU(2)\times U(1)$ doublet and a new symmetry,…
We review the empirical evidence for the validity of the Standard Electroweak Theory in nature. The experimental data are interpreted in terms of an effective Lagrangian for Z physics, allowing for potential sources of SU(2) violation and…
In a recent paper, we introduced a new Little Higgs model, which contains the gauge structure $SU(2)^3\times U(1)$, embedded in an approximate global $SO(5)\times SO(5)$ symmetry. After breaking to the standard model, $SU(2)_L \times…
We derive the leptonic neutral current in the simplest little Higgs model and compute the contribution of the model to the decay width $Z \to e^+e^-$. Using the precision electroweak data we obtain a strong lower bound $f\geq 5.6$ TeV at…
We update the analysis of the precision electroweak tests in terms of 4 epsilon parameters, $\epsilon_{1,2,3,b}$, to obtain more accurate experimental values of them by taking into account the new LEP data released at the 28th ICHEP (1996,…
The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the…
Triple gauge boson couplings between Z, gamma and the W boson are determined by exploiting their impact on radiative corrections to fermion-pair production in e+e- interactions at centre-of-mass energies near the Z-pole. Recent values of…
Recently, the CDF collaboration reported a new measurement of the $W$ boson mass $M_W = 80.4335 \pm 0.0094$ GeV, which shows a $\sim 7\sigma$ deviation from the standard model prediction $80.3545 \pm 0.0057$ GeV obtained by the electroweak…
An extension of the Standard Model to the local gauge group $SU(3)_c\otimes SU(3)_L\otimes U(1)_X$ which is a subgroup of the electroweak-strong unification group $E_6$ is analyzed. The mass scales, the gauge boson masses, and the masses…
The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic $e^+p$ and $e^-p$ neutral current and charged current scattering cross sections published by the H1 Collaboration,…
Comparing the theoretically predicted and measured values of the mass difference of the $B^{0}_{s}$ system, we estimate the lower bound on the mass of the $Z^{\prime}$ boson of models based on the $SU(3)_{c} \otimes SU(3)_{L} \otimes…
We examine the decay of $Z_1$ in electrons with recent data from LEP. The partial width $\Gamma(Z_1\to e^-e^+)$ is studied in the framework of a left-right symmetric model with standard electroweak corrections. Processes measured near the…
Precision measurements of $Z$-boson parameters and $W$-boson and $t$-quark masses put strong constraints on non $SU(2)\times U(1)$ singlet New Physics. We demonstrate that one extra generation passes electroweak constraints even when all…