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Standard-model fields and their associated electroweak Lagrangian are equivalently expressed in a shared spin basis. The scalar-vector terms are written with scalar-operator components acting on quark-doublet elements, and shown to be…

High Energy Physics - Phenomenology · Physics 2019-04-10 J. Besprosvany , R. Romero

We investigate the impact of dark Abelian gauge bosons on the electroweak precision measurements at the one-loop level. The dark gauge boson couples to the standard model fermions generally via two kinds of mixing with the electroweak gauge…

High Energy Physics - Phenomenology · Physics 2026-01-15 Cheng-Wei Chiang , Kazuki Enomoto

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…

High Energy Physics - Phenomenology · Physics 2007-05-23 Dieter Schildknecht

A model of electroweak-scale right-handed neutrino (\ewnur) model was constructed five years ago in which the right-handed neutrinos are members of mirror fermion weak doublets and where the Majorana masses of the right-handed neutrinos are…

High Energy Physics - Phenomenology · Physics 2013-10-22 Vinh Hoang , Pham Q. Hung , Ajinkya Kamat

We calculate the tree-level electroweak precision constraints on a wide class of little Higgs models including: variations of the Littlest Higgs SU(5)/SO(5), SU(6)/Sp(6), and SU(4)^4/SU(3)^4. By performing a global fit to the precision data…

High Energy Physics - Phenomenology · Physics 2009-09-17 C. Csaki , J. Hubisz , G. D. Kribs , P. Meade , J. Terning

The Lee-Wick (LW) formulation of higher-derivative theories can be extended from one in which the extra degrees of freedom are represented as a single heavy, negative-norm partner for each known particle (N=2), to one in which a second,…

High Energy Physics - Phenomenology · Physics 2013-05-30 Richard F. Lebed , Russell H. TerBeek

The STU formalism of Peskin and Takeuchi is an elegant method for encoding the measurable effects of new physics which couples to light fermions dominantly through its effects on electroweak boson propagation. However, this formalism cannot…

High Energy Physics - Phenomenology · Physics 2019-08-17 C. P. Burgess , S. Godfrey , H. Konig , D. London , I. Maksymyk

In a previous analysis presented in hep-ph/0412166, electroweak constraints were given on arbitrary linear combinations of a set of dimension-6 operators. Flavor universality and thus U(3)^5 flavor symmetry were assumed for the operators.…

High Energy Physics - Phenomenology · Physics 2009-11-11 Zhenyu Han

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…

Many models of Beyond the Standard Model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In…

High Energy Physics - Phenomenology · Physics 2013-05-30 S. Dawson , E. Furlan

We update our previous work on an analysis of the electroweak data by including new and partly preliminary data available up to the 1996 summer conferences. The new results on the Z partial decay widths into b and c hadrons now offer a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Kaoru Hagiwara , Dieter Haidt , Seiji Matsumoto

We perform the fit of electroweak precision observables within the Standard Model with a 126 GeV Higgs boson, compare the results with the theoretical predictions and discuss the impact of recent experimental and theoretical improvements.…

High Energy Physics - Phenomenology · Physics 2015-06-16 Marco Ciuchini , Enrico Franco , Satoshi Mishima , Luca Silvestrini

We consider an extension of the standard electroweak theory with gauge group $SU(2)_L \times SU(2)_R \times U(1)_{\tilde{Y}}$, where the gauge bosons of the extra $SU(2)_R$ factor do not couple to ordinary fermions. We show that precision…

High Energy Physics - Phenomenology · Physics 2009-10-30 A. Donini , F. Feruglio , J. Matias , F. Zwirner

Using a general (non-linear) effective field theory description of the Standard Model electroweak symmetry breaking, we analyse the impact on the electroweak oblique parameters of hypothetical heavy resonance states strongly coupled to the…

High Energy Physics - Phenomenology · Physics 2025-03-11 Antonio Pich , Ignasi Rosell , Juan José Sanz-Cillero

In the standard model of electroweak interactions the Higgs doublet is replaced by a complex vector doublet and a real vector singlet. The gauge symmetry is broken dynamically by a mixed condensate of the doublet and singlet vector fields.…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Cynolter , E. Lendvai , G. Pocsik

We study symmetry breaking in a left-right symmetric extension of the Standard Model with mirror fermions, one for each Standard-Model fermion. The new particles assist a top-quark condensate in breaking electro-weak symmetry. Half of the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Manfred Lindner , George Triantaphyllou

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…

High Energy Physics - Phenomenology · Physics 2009-11-10 Guido Altarelli , Martin W. Grunewald

Extra-dimensional Higgsless models with electroweak symmetry breaking through boundary conditions generically have difficulties with electroweak precision constraints, when the fermions are localized to the ``branes'' in the fifth…

High Energy Physics - Phenomenology · Physics 2010-04-05 Roshan Foadi , Shrihari Gopalakrishna , Carl Schmidt

Many types of physics beyond the standard model include an extended electroweak gauge group. If these extensions are associated with flavor symmetry breaking, the gauge interactions will not be flavor-universal. In this note we update the…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. S. Chivukula , E. H. Simmons

A reexamination is made of one-loop oblique electroweak corrections. General definitions are given of the oblique parameters without reference to any $q^2$-expansion scheme. The old oblique parameters S,T and U are defined as differences of…

High Energy Physics - Phenomenology · Physics 2014-11-17 Anirban Kundu , Probir Roy