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Recently, Higgsless models have proven to be viable alternatives to the Standard Model (SM) and supersymmetric models in describing the breaking of the electroweak symmetry. Whether extra-dimensional in nature or their deconstructed…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Dawson , C. B. Jackson

We study the three-loop Euler-Heisenberg Lagrangian in spinor quantum electrodynamics in 1+1 dimensions. In this first part we calculate the one-fermion-loop contribution, applying both standard Feynman diagrams and the worldline formalism…

High Energy Physics - Theory · Physics 2019-05-01 Idrish Huet , Michel Rausch de Traubenberg , Christian Schubert

Chiral perturbation theory in the anomaly sector for $N_f=2$ is extended to include dynamical photons, thereby allowing a complete treatment of isospin breaking. A minimal set of independent chiral lagrangian terms is determined and the…

High Energy Physics - Phenomenology · Physics 2014-11-17 B. Ananthanarayan , B. Moussallam

We parameterize the non-universal couplings of t-t-Z and t-b-W in the electroweak chiral lagrangian approach, and examine the constraints on these parameters from the LEP data. We also study how the SLC, Tevatron, LHC and NLC can improve…

High Energy Physics - Phenomenology · Physics 2009-10-28 Douglas O. Carlson , Ehab Malkawi , C. --P. Yuan

The properties of the effective field theory relevant for the low energy structure generated by the Goldstone bosons of a spontaneously broken symmetry are reexamined. It is shown that anomaly free, Lorentz invariant theories are…

High Energy Physics - Phenomenology · Physics 2009-10-22 H. Leutwyler

We parametrize in a model-independent way possible departures from the minimal Standard Model predictions in the matter sector. We only assume the symmetry breaking pattern of the Standard Model and that new particles are sufficiently heavy…

High Energy Physics - Phenomenology · Physics 2016-08-25 Emili Bagan , Domenec Espriu , Julian Manzano

Charm and bottom mesons and baryons are incorporated into a low energy chiral Lagrangian. Interactions of the heavy hadrons with light octet Goldstone bosons are studied in a framework which represents a synthesis of chiral perturbation…

High Energy Physics - Phenomenology · Physics 2010-11-01 Peter Cho

In this talk I concentrate on the role of chiral symmetry realisation by spin-1 fields in the low energy QCD effective lagrangian. I assume that chiral symmetry is nonlinearly realised and that spin-1 fields transform homogeneously under…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Kalafatis

We present a unified analysis of the two main production processes of vector boson pairs at the LHC, VV-fusion and qqbar annihilation, in a minimal strongly interacting electroweak symmetry breaking sector. Using a unitarized electroweak…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Dobado , M. J. Herrero , J. R. Pelaez , E. Ruiz Morales

By bosonization of an extended NJL model we derive an effective meson theory which describes the interplay between chiral symmetry and heavy quark dynamics. This effective theory is worked out in the low-energy regime using the gradient…

High Energy Physics - Phenomenology · Physics 2009-10-28 D. Ebert , T. Feldmann , R. Friedrich , H. Reinhardt

We review the techniques necessary for the calculation of virtual electroweak and soft photonic corrections at the one-loop level. In particular we describe renormalization, calculation of one-loop integrals and evaluation of one-loop…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ansgar Denner

We present an extension of chiral perturbation theory that explicitly includes an isosinglet scalar in the Lagrangian. The dynamical effects from the scalar state is of phenomenological relevance in theories where the mass of the isosinglet…

High Energy Physics - Phenomenology · Physics 2019-06-04 Martin Hansen , Kasper Langæble , Francesco Sannino

Whether there exists a massive electroweak (EW) theory, without a Higgs spontaneous symmetry breaking mechanism, that is gauge invariant and renormalizable is investigated. A Stueckelberg formalism for massive $W$ and $Z$ bosons is used to…

High Energy Physics - Phenomenology · Physics 2011-10-19 J. W. Moffat

We study large top quark mass effects on low energy physics in the chiral Lagrangian formulated electroweak theories. We show that these radiative corrections can be easily obtained from a set of Feynman diagrams involving only the scalar…

High Energy Physics - Phenomenology · Physics 2009-10-28 Ehab Malkawi , C. --P. Yuan

We show that the one-loop Euler-Heisenberg QED effective Lagrangian in a constant background field acquires a very different non-perturbative trans-series structure at two-loop and higher-loop order in the fine structure constant. Beyond…

High Energy Physics - Theory · Physics 2021-03-31 Gerald V. Dunne , Zachary Harris

We include the eta-prime in chiral perturbation theory without employing 1/N_c counting rules. The method is illustrated by calculating the masses and decay constants of the Goldstone boson octet (pions, kaons, eta) and the singlet…

High Energy Physics - Phenomenology · Physics 2009-11-07 B. Borasoy , S. Wetzel

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 D. Schildknecht

Electroweak baryogenesis is briefly overviewed with emphasis on nondecoupling loop properties of the scalar particles. In particular, quantum corrections to the triple Higgs boson coupling is discussed as a probe of electroweak…

High Energy Physics - Phenomenology · Physics 2013-05-21 Eibun Senaha

In the context of the minimal SO(5) linear {\sigma}-model, a complete renormalizable Lagrangian -including gauge bosons and fermions- is considered, with the symmetry softly broken to SO(4). The scalar sector describes both the electroweak…

High Energy Physics - Phenomenology · Physics 2016-06-29 Ferruccio Feruglio , Belen Gavela , Kirill Kanshin , Pedro Accioly Nogueira Machado , Stefano Rigolin , Sara Saa

We consider the Standard Model as an effective theory at the weak scale $v$ of a generic new strong interaction that dynamically breaks electroweak symmetry at the energy scale $\Lambda\sim $ (few) TeV. Assuming only the minimal field…

High Energy Physics - Phenomenology · Physics 2015-06-04 Gerhard Buchalla , Oscar Cata