Related papers: Oblique Parameters and Extra Generations via OPUCE…
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,…
Precision electroweak physics can provide fertile ground for uncovering new physics beyond the Standard Model (SM). One area in which new physics can appear is in so-called "oblique corrections", i.e., next-to-leading order expansions of…
The contribution to precision electroweak measurements due to TeV physics which couples primarily to the $W^\pm$ and $Z$ bosons may be parameterized in terms of the three `oblique correction' parameters, S, T and U. We extend this…
We calculate the strength of the electroweak phase transition in a supersymmetric model with four chiral generations. The additional chiral fermions (and scalar partners) lower the critical temperature and thus strengthen the first-order…
We calculate the contributions to electroweak precision observables (EWPOs) due to a fourth generation of fermions with the most general (quark-)flavour structure (but assuming Dirac neutrinos and a trivial flavour structure in the lepton…
Talks presented at Beyond The Standard Model IV Conference, Lake Tahoe, Dec 94: NEW FERMION FAMILIES AND PRECISION ELECTROWEAK DATA: We highlight a trend in the precision electroweak data towards light new physics and argue that some…
We show how precision electroweak data, assuming CP conservation and flavor universality, despite being sensitive to 20 dimension 6 operators, constrain severely only 9 combinations of them. We define a set of 7 oblique parameters $\hat S,…
Extending the Standard Model with right-handed neutrinos provides a minimal explanation for both light neutrino masses (through the type-I seesaw mechanism) and the baryon asymmetry of our universe (through leptogenesis). We map here for…
We study radiative corrections to the electroweak parameters in the Higgs model with the Y=1 triplet field, which is introduced in the scenario of generating neutrino masses based on the so-called type II seesaw mechanism. In this model,…
We refine our recent analysis of the electroweak precision data at the \PZO\ pole by including the hadronic decay modes of the \PZO. Within the framework of an effective Lagrangian we parametrize $SU(2)$ violation by the additional…
We compute the leading corrections to the properties of W and Z bosons induced at the one-loop level in the SU(5)/SO(5) Littlest Higgs model with T parity, and perform a global fit to precision electroweak data to determine the constraints…
The Standard Model global fit to precision data is excellent. The Minimal Supersymmetric Standard Model can also fit the data well, though not as well as the Standard Model. At best, supersymmetric contributions either decouple or only…
The global electroweak fit of the Standard Model (SM) with Gfitter can be used to constrain yet unknown SM parameters, such as the Higgs mass, but also physics beyond the SM (BSM) via the formalism of oblique parameters. This paper presents…
We perform an analysis of the behaviour of the electroweak phase transition in the Minimal Supersymmetric Standard Model, in the presence of light stops. We show that, in previously unexplored regions of parameter space, the order parameter…
Precise measurements of Z-boson parameters and W-boson and t-quark masses put strong constraints on non SU(2) * U(1) singlet New Physics. We demonstrate that one extra generation passes electroweak constraints even when all new particle…
This summary of the 3rd "Beyond the 3 Generation Standard Model" workshop presents the following four statements (and their implications) for the ongoing and future searches of a fourth generation: 1) The enhancement of the Higgs…
It is shown that additional chiral generations are not excluded by the latest electroweak precision data if one assumes that there is no mixing with the known three generations. In the case of ``heavy extra generations'', when all four new…
In an extension of the Standard Model with a scalar color octet, the possibility of the strongly first-order electroweak phase transition is studied, by examining the finite-temperature effective Higgs potential at the one-loop level. It is…
Oblique radiative corrections are calculated to the parameter $S$ in a version of the standard model where the Higgs doublet is replaced by a doublet of vector bosons and the gauge symmetry is broken dynamically. We show that to each…
We analyse the impact of LHC and Tevatron Higgs data on the viability of the Standard Model with a sequential fourth generation (SM4), assuming Dirac neutrinos and a Higgs mass of 125 GeV. To this end we perform a combined fit to the signal…