Related papers: Z' near the Z-pole
We show that a Z' with suppressed couplings to the electron compared to the Z-boson, with couplings to the b-quark, and with a mass close to the mass of the Z-boson, provides an excellent fit to forward-backward asymmetry of the b-quark and…
The couplings of the fermions to the Z boson are of great importance in establishing the validity of the Standard Model and in looking for physics beyond it. The couplings of the b-quark to the Z boson have been the subject of much…
In order to explain possible departures from the Standard Model predictions for $b\bar b$ and $c\bar c$ production at $Z$ peak, we propose the existence of a $Z'$ vector boson with enhanced couplings to quarks. We first show that this…
We discuss three promising diagnostic probes of the couplings of a possible heavy $Z'$ boson at hadron colliders: the forward-backward asymmetry into leptons, the rare decay $Z' \ra W^{\pm} \ell^{\mp} \nu$, and associated production $pp \ra…
The sensitivity of top quark pair production at the Large Hadron Collider to the presence and nature of an underlying Z' boson is studied, accounting for six-fermion decay with full tree-level Standard Model ttbar interference and all…
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…
Model-independent search for the Abelian Z' gauge boson in the Drell-Yan process at the LHC at s^{1/2}= 7 TeV and 8 TeV is fulfilled. Estimations of the Z' axial-vector coupling a_f^2 to the standard model fermions, the couplings of the…
We point out that at future hadron colliders the ratio of cross sections for $pp\to Z'\to \ell^+\ell^-$ in two rapidity bins is a useful probe of the relative couplings of the $Z'$ to $u$ and $d$ quarks. Combined with the forward-backward…
The study of electroweak boson pair production provides a powerful test of the spontaneously broken gauge symmetry of the Standard Model (SM) and can be used to search for new phenomena beyond the SM. Extra neutral vector bosons $Z'$…
The Randall-Sundrum scenario with Standard Model fields in the bulk and a custodial symmetry is considered. We determine the several minimal quark representations allowing to address the anomalies in the forward-backward b-quark asymmetry…
The paper deals with an approach to the model-independent searching for the Z' gauge boson as a virtual state in scattering processes. The relations between the Z' couplings to fermions covering a wide class of models beyond the standard…
Among the $Z$-pole observables, $A_{FB}^{(0,b)}$ and $A_e$ suffer moderately-large standard deviations from the Standard Model predictions. Fine-tuning of the unknown Higgs mass only reduces the deviation of one of them at the expense of…
Electroweak Precision Measurements are stringent tests of the Standard Model and sensitive probes to New Physics. Accurate studies of the $Z$-boson couplings to the first-generation quarks, which are currently constrained from LEP data to a…
A model independent analysis is made using the LEP and SLD data on Z decays available at the end of 1996. The effective weak coupling constants of leptons, c quarks and b quarks are extracted. Except for the right-handed b quark coupling,…
Many new physics models predict the existence of extra neutral gauge bosons ($Z'$). Inspired by the recent development on Higgs search, we study the properties of $Z'$ via the Higgs and $Z$ boson associated production. The couplings of $Z'$…
The proposed Large Hadron Electron Collider (LHeC), with center-of-mass energy of $\sqrt{s}\approx 1.3$ TeV, provides a clean and sensitive environment to probe the top quark's neutral current interactions with the $Z$ boson via the process…
We report on our re-calculation of electroweak top-quark pair production in Standard Model extensions with extra heavy neutral and charged spin-1 particles at the LHC with substantial improvements. In particular, we allow for…
This note presents a combination of published and preliminary electroweak results from the four LEP collaborations and the SLD collaboration which were prepared for the 2002 summer conferences. Averages from Z resonance results are derived…
We study constraints on additional $Z'$ bosons predicted in the supersymmetric (SUSY) $E_6$ models by using the updated results of electroweak experiments -- $Z$-pole experiments, $m_W$ measurements and low-energy neutral current (LENC)…
We analyze various models with an extra U(1) gauge symmetry in addition to the Standard Model (SM) gauge group at low energies, and impose limits on the mass of the neutral Z' boson, M_Z', predicted in all such models, and on the Z-Z'…