Related papers: Improved Constraints on Z' Bosons from Electroweak…
We show that some models with $SU(3)_C\otimes SU(3)_L\otimes U(1)_X$ gauge symmetry can be realized at the electroweak scale and that this is a consequence of an approximate global $SU(2)_{L+R}$ symmetry. This symmetry implies a condition…
New gauge bosons with Standard Model-like couplings to leptons are constrained by collider searches to be heavier than approximately ~1 TeV. A Z' boson with suppressed couplings to leptons, however, could be much lighter and possess…
We revisit the CDF data on di-muon production to impose constraints on a large class of Z' bosons occurring in a variety of E_6 GUT based models. We analyze the dependence of these limits on various factors contributing to the production…
The viable window to electroweak baryogenesis in a supersymmetric $U(1)'$ model is studied in light of the 126 GeV Higgs boson. To investigate the decoupling of the sphaleron process in the broken phase, we evaluate the sphaleron rate and…
An updated global analysis within the Standard Model (SM) of all relevant electroweak precision and Higgs boson search data is presented with special emphasis on the implications for the Higgs boson mass, M_H. Included are, in particular,…
The fit of precision electroweak data to the Minimal Standard Model currently gives an upper limit on the Higgs boson mass of 170 GeV at 95% confidence. Nevertheless, it is often said that the Higgs boson could be much heavier in more…
The precise determination of the $W$ boson mass, $m_W$, is a cornerstone of electroweak precision tests and a critical input to global fits of the Standard Model (SM). While most existing measurements of $m_W$ are in agreement with SM…
The LEP data and the measurement of $M_W$ confirm the electro weak symmetry breaking by the Higgs mechanism with (2--3)\% accuracy. For the Higgs boson mass, fits to the present data (without the SLD result) give $M_h=121^{+207}_{-118}$ GeV…
I present a scenario wherein heavy neutral vector bosons Z', predicted by GUT-inspired U(1)' models, decay into supersymmetric final states, besides the Standard Model channels investigated at the LHC. It is found that accounting for such…
We present Standard Model predictions for the complete set of phenomenologically relevant electroweak precision pseudo-observables related to the Z-boson: the leptonic and bottom-quark effective weak mixing angles $\sin^2\theta_{\rm…
We perform a global analysis of electroweak precision measurements to find constraints on physics beyond the Standard Model. In particular, we discuss oblique parameters, which are useful to constrain additional matter fields, as well as…
Supersymmetric unified models in which the Z' couples to the Higgs doublets, as in the E6 class of models, have large fine tuning dominated by the experimental mass limit on the Z'. To illustrate this we investigate the degree of fine…
The utility of precision electroweak measurements for predicting the Standard Model Higgs mass via quantum loop effects is discussed. Current constraints from $m_W$ and $\sinsthw\mzms$ imply a relatively light Higgs $\lsim 154$ GeV which is…
This note presents constraints on Standard Model parameters using published and preliminary precision electroweak results measured at the electron-positron colliders LEP and SLC. The results are compared with precise electroweak…
Applying No-Scale Supergravity boundary conditions at a heavy unification scale to the Flipped $SU(5)$ grand unified theory with extra TeV-scale vector-like multiplets, $i.e.$ No-Scale ${\cal F}$-$SU(5)$, we express the $Z$-boson mass $M_Z$…
We systematically analyze the anomalous dipole $\Delta k_{\gamma}$ and quadrupole $\Delta Q_{\gamma}$ moments of the W gauge bosons in the context of the minimal supersymmetric standard model as functions of the soft SUSY breaking…
In models with universal extra dimensions (UED), the lightest Kaluza-Klein excitation of neutral electroweak gauge bosons is a stable, weakly interacting massive particle and thus is a candidate for dark matter thanks to Kaluza-Klein…
There are two aspects to the 1995 summer update of the combined preliminary electroweak data from LEP and SLC. On the one hand, agreement between experiments and the Standard Model (SM) has improved for the line-shape and the asymmetry…
We calculate the electroweak corrections to the production of WWZ and ZZZ at the linear collider in the Standard Model. These processes are important for the extraction of the quartic couplings of the massive gauge bosons which can be a…
Electroweak precision observables, being highly sensitive to loop contributions of new physics, provide a powerful tool to test the theory and to discriminate between different models of the underlying physics. In that context, the $W$…