scholarly journals PROBING ELECTROWEAK SYMMETRY BREAKING MECHANISM AT THE LHC: A GUIDELINE FROM POWER COUNTING ANALYSIS

1996 ◽  
Vol 11 (39n40) ◽  
pp. 3061-3074 ◽  
Author(s):  
HONG-JIAN HE ◽  
YU-PING KUANG ◽  
C.-P. YUAN

We formulate the equivalence theorem as a theoretical criterion for sensitively probing the electroweak symmetry breaking mechanism, and develop a precise power counting method for the chiral Lagrangian formulated electroweak theories. Armed with these, we perform a systematic analysis on the sensitivities of the scattering processes W±W±→W±W± and [Formula: see text] for testing all possible effective bosonic operators in the chiral Lagrangian formulated electroweak theories at the CERN Large Hadron Collider (LHC). The analysis shows that these two kinds of processes are complementary in probing the electroweak symmetry breaking sector.

2011 ◽  
Vol 26 (02) ◽  
pp. 87-100
Author(s):  
JAMES MAXIN ◽  
VAN E. MAYES ◽  
D. V. NANOPOULOS

No-scale supergravity is a framework where it is possible to naturally explain radiative electroweak symmetry breaking and correlate it with the effective SUSY breaking scale. Many string compactifications have a classical no-scale structure, resulting in a one-parameter model (OPM) for the supersymmetry breaking soft terms, which results in a highly constrained subset of mSUGRA. We investigate the allowed supersymmetry parameter space for a generic one-parameter model taking into account the most recent experimental constraints. We also survey the possible signatures which may be observable at the Large Hadron Collider (LHC). Finally, we compare collider signatures of OPM to those from a model with non-universal soft terms, in particular those of an intersecting D6-brane model.


2013 ◽  
Vol 28 (02) ◽  
pp. 1330004 ◽  
Author(s):  
ALEKSANDR AZATOV ◽  
JAMISON GALLOWAY

In this review, we discuss methods of parsing direct information from collider experiments regarding the Higgs boson and describe simple ways in which experimental likelihoods can be consistently reconstructed and interfaced with model predictions in pertinent parameter spaces. We review prevalent scenarios for extending the electroweak symmetry breaking sector and emphasize their predictions for nonstandard Higgs phenomenology that could be observed in large hadron collider (LHC) data if naturalness is realized in particular ways. Specifically we identify how measurements of Higgs couplings can be used to imply the existence of new physics at particular scales within various contexts. The most dominant production and decay modes of the Higgs-like state observed in the early data sets have proven to be consistent with predictions of the Higgs boson of the Standard Model, though interesting directions in subdominant channels still exist and will require our careful attention in further experimental tests. Slightly anomalous rates in certain channels at the early LHC have spurred effort in model building and spectra analyses of particular theories, and we discuss these developments in some detail. Finally, we highlight some parameter spaces of interest in order to give examples of how the data surrounding the new state can most effectively be used to constrain specific models of weak scale physics.


2020 ◽  
pp. 8-12
Author(s):  
T.V. Obikhod ◽  
E.A. Petrenko

Models with extended Higgs boson sectors are of prime importance for investigating the mechanism of electroweak symmetry breaking for Higgs decays into four fermions and for Higgs-production in association with a vector bosons. In the framework of the Two-Higgs-Doublet Model using two scenarios obtained from the experimental measurements we presented next-to-leading-order results on the four-fermion decays of light CP-even Higgs boson, h → 4f. With the help of Monte Carlo program Prophecy 4f 3.0, we calculated the values Γ = ΓEW/(ΓEW + ΓSM) and Γ = ΓEW+QCD/(ΓEW+QCD + ΓSM) for Higgs boson decay channels H → νµµeνe, µµee, eeee. We didn’t find significant difference when accounting QCD corrections to EW processes in the decay modes of Higgs boson. Using computer programs Pythia 8.2 and FeynHiggs we calculated the following values: σ(V BH)BR(H → ZZ) and σ(V BF)BR(H → WW) for VBF production processes, σ(ggH)BR(H → WW) and σ(ggH)BR(H → ZZ) for gluon fusion production process at 13 and 14 TeV and found good agreement with experimental data.


2008 ◽  
Vol 23 (22) ◽  
pp. 3509-3523 ◽  
Author(s):  
L. CLAVELLI

From several points of view, it is strongly suggested that the current universe is unstable and will ultimately decay to one that is exactly supersymmetric (SUSY). The possibility that atoms and molecules form in this future universe requires that the degenerate electron/selectron mass is non-zero and hence that electroweak symmetry breaking (EWSB) survives the phase transition to exact SUSY. However, the Minimal Supersymmetric Standard Model (MSSM) and several of its extensions have no EWSB in the SUSY limit. Among the extended Higgs models that have been discussed, one stands out in this regard. The Higgs sector that is revealed at the Large Hadron Collider (LHC) will therefore have implications for the future universe. We also address the question as to whether the transition to the exact SUSY phase with EWSB is exothermic.


Symmetry ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 312
Author(s):  
Wei-Shu Hou

The 125 GeV boson is quite consistent with the Higgs boson of the Standard Model (SM), but there is a challenge from Anderson as to whether this particle is in the Lagrangian. As Large Hadron Collider (LHC) Run 2 enters its final year of running, we ought to reflect and make sure we have gotten everything right. The ATLAS and CMS combined Run 1 analysis claimed a measurement of 5.4σ vector boson fusion (VBF) production which is consistent with SM, which seemingly refutes Anderson. However, to verify the source of electroweak symmetry breaking (EWSB), we caution that VBF measurement is too important for us to be imprudent in any way, and gluon–gluon fusion (ggF) with similar tag jets must be simultaneous measured, which should be achievable in LHC Run 2. The point is to truly test the dilaton possibility—the pseudo-Goldstone boson of scale invariance violation. We illustrate EWSB by dynamical mass generation of a sequential quark doublet (Q) via its ultrastrong Yukawa coupling and argue how this might be consistent with a 125 GeV dilaton, D. The ultraheavy 2mQ≳4–5 TeV scale explains the absence of New Physics so far, while the mass generation mechanism shields us from the UV theory for the strong Yukawa coupling. Collider and flavor physics implications are briefly touched upon. Current Run 2 analyses show correlations between the ggF and VBF measurements, but the newly observed tt¯H production at LHC poses a challenge.


1995 ◽  
Vol 51 (11) ◽  
pp. 6463-6473 ◽  
Author(s):  
Hong-Jian He ◽  
Yu-Ping Kuang ◽  
C.-P. Yuan

2013 ◽  
Vol 28 (18) ◽  
pp. 1330027 ◽  
Author(s):  
EMANUELA BARBERIS

An experimental review of the current status of the top quark physics program at hadron colliders is presented. Since the discovery of the top quark at the Fermilab Tevatron collider in 1995, its production and the decay have been studied with an extraordinary level of sophistication both at the Tevatron and at the Large Hadron Collider. The top quark is the heaviest known elementary particle, with possible unique connections to the mechanism of electroweak symmetry breaking.


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