Dynamical Electroweak Symmetry Breaking At Tevatron Run Ii And Lhc (original) (raw)

Electroweak Symmetry Breaking at the LHC

Physics at the Large Hadron Collider, 2009

One of the major goals of the Large Hadron Collider is to probe the electroweak symmetry breaking mechanism and the generation of the masses of the elementary particles. We review the physics of the Higgs sector in the Standard Model and some of its extensions such as supersymmetric theories and models of extra dimensions. The prospects for discovering the Higgs particles at the LHC and the study of their fundamental properties are summarised.

Strong dynamics and electroweak symmetry breaking

Physics Reports, 2003

The breaking of electroweak symmetry, and origin of the associated "weak scale," v weak = 1/ 2 √ 2G F = 175 GeV, may be due to a new strong interaction. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Many of these schemes feature a privileged role for the top quark, and third generation, and are natural in the context of theories of extra space dimensions at the weak scale. We review various models and their phenomenological implications which will be subject to definitive tests in future collider runs at the Tevatron, and the LHC, and future linear e + e − colliders, as well as sensitive studies of rare processes. 5 Outlook and Conclusions 159 6 Acknowledgements 160 Appendix A: The Standard Model 161 Appendix B: The Nambu-Jona-Lasinio Model 168 Bibliography 172

Dynamical Electroweak Symmetry Breaking at the LHC

I briefly review the basic challenges and virtues of models breaking the electroweak symmetry dynamically. I will then introduce the (ultra) minimal walking technicolor models whose construction has been made possible thanks to recent progress in the understanding of the phase diagram for strongly coupled theories as function of number of flavors, colors and matter representation. I will mention possible relevant collider signatures. Interestingly, asymmetric Dark Matter is a natural possibility in our models providing interesting candidates for decaying Dark Matter models which have been explored to account for the PAMELA and ATIC excesses in e ± cosmic rays.

Electroweak symmetry breaking and beyond the Standard Model physics — A review

Pramana, 2009

In this talk, I shall first discuss the standard model Higgs mechanism and then highlight some of its deficiencies making a case for the need to go beyond the standard model (BSM). The BSM tour will be guided by symmetry arguments. I shall pick up four specific BSM scenarios, namely, supersymmetry, Little Higgs, Gauge-Higgs unification, and the Higgsless approach. The discussion will be confined mainly on their electroweak symmetry breaking aspects.

Dynamical Electroweak Symmetry Breaking with a Heavy Fermion in Light of Recent LHC Results

Advances in High Energy Physics, 2013

The recent announcement of a discovery of a possible Higgs-like particle—its spin and parity are yet to be determined—at the LHC with a mass of 126 GeV necessitates a fresh look at the nature of the electroweak symmetry breaking, in particular if this newly-discovered particle will turn out to have the quantum numbers of a Standard Model Higgs boson. Even if it were a 0+scalar with the properties expected for a SM Higgs boson, there is still the quintessential hierarchy problem that one has to deal with and which, by itself, suggests a new physics energy scale around 1 TeV. This paper presents a minireview of one possible scenario: the formation of a fermion-antifermion condensate coming from a very heavy fourth generation, carrying the quantum number of the SM Higgs field, and thus breaking the electroweak symmetry.

A Strongly Interacting Electroweak Symmetry Breaking Sector with a Higgs-like light scalar

The apparent finding of a 125 GeV light Higgs boson would close the minimal Standard Model (SM), that is weakly interacting. This is an exceptional feature not generally true if new physics exists beyond the mass gap found at the LHC up to 700 GeV. Any such new physics would induce departures from the SM in the low-energy dynamics for the minimal electroweak symmetry-breaking sector (EWSBS), with three Goldstone bosons (related to longitudinal W and Z bosons) and one light Higgs-like scalar. With no new particle content, for most of the parameter space, the scattering is actually strongly interacting (with the SM a remarkable exception). We therefore explore various unitarization methods, that have already be applied to the tree-level WL WL amplitude; we find and study a natural second sigma-like scalar pole there. Of note is its appearance due to either elastic or coupled-channel dynamics, especially since the later is largely unconstrained by current LHC data and could be large.

Discovering Higgsless Electroweak Symmetry Breaking at LHC8

2012

We study the physics potential of the 8 TeV LHC (LHC-8) to discover, during its 2012 run, a large class of extended gauge models or extra dimensional models whose low energy behavior is well represented by an SU (2) 2 ⊗ U (1) gauge structure. We analyze this class of models and find that with a combined integrated luminosity of 40 − 60 fb −1 at the LHC-8, the first new Kaluza-Klein mode of the W gauge boson can be discovered up to a mass of about 370 − 400 GeV, when produced in association with a Z boson.

Electroweak and supersymmetry breaking from the Higgs boson discovery

Physical Review D, 2014

We will explore the consequences on the electroweak breaking condition, the mass of supersymmetric partners and the scale at which supersymmetry breaking is transmitted, for arbitrary values of the supersymmetric parameters tan β and the stop mixing X t , which follow from the Higgs discovery with a mass m H ≃ 126 GeV at the LHC. Within the present uncertainty on the top quark mass we deduce that radiative breaking requires tan β ≳ 8 for maximal mixing X t ≃ ffiffi ffi 6 p , and tan β ≳ 20 for small mixing X t ≲ 1.8. The scale at which supersymmetry breaking is transmitted M can be of order the unification or Planck scale only for large values of tan β and negligible mixing X t ≃ 0. On the other hand for maximal mixing and large values of tan β supersymmetry should break at scales as low as M ≃ 10 5 GeV. The uncertainty in those predictions stemming from the uncertainty in the top quark mass, i.e. the top Yukawa coupling, is small (large) for large (small) values of tan β. In fact for tan β ¼ 1 the uncertainty on the value of M is several orders of magnitude.

Future Directions in Higgs Phenomenology

The search for the weakly-coupled Higgs sector at future colliders consists of three phases: discovery of a Higgs candidate, verification of the Higgs interpretation of the signal, and precision measurements of Higgs sector properties. The discovery of one Higgs boson with Standard Model properties is not sufficient to expose the underlying structure of the electroweak symmetry breaking dynamics. It is critical to search for evidence for a non-minimal Higgs sector and/or new physics associated with electroweak symmetry breaking dynamics.

Towards a Realistic Model of Higgsless Electroweak Symmetry Breaking

Physical Review Letters, 2004

We present a 5D gauge theory in warped space based on a bulk SU (2) L × SU (2) R × U (1) B−L gauge group where the gauge symmetry is broken by boundary conditions. The symmetry breaking pattern and the mass spectrum resembles that in the standard model (SM). To leading order in the warp factor the ρ parameter and the coupling of the Z (or equivalently the S-parameter) are as in the SM, while corrections are expected at the level of a percent. From the AdS/CFT point of view the model presented here can be viewed as the AdS dual of a (walking) technicolor-like theory, in the sense that it is the presence of the IR brane itself that breaks electroweak symmetry, and not a localized Higgs on the IR brane (which should be interpreted as a composite Higgs model). This model predicts the lightest W , Z and γ resonances to be at around 1.2 TeV, and no fundamental (or composite) Higgs particles. * Other interesting possibilities for EWSB using extra dimensions is to have the Higgs be the extra dimensional component of a gauge field, see for example , or to have a warped compactification where the would-be zero mode for the gauge field is not normalizable .