Related papers: Hints of Dynamical Symmetry Breaking?
After the Higgs boson discovery, it is established that the Higgs mechanism explains electroweak symmetry breaking and generates the masses of all particles in the Standard Model, with the possible exception of neutrino masses. The…
We show how a dynamical Majorana mass for a fourth family left-handed neutrino can make a significant negative contribution to the electroweak correction parameter T without making a large contribution to S or U. We also comment on other…
A model is presented in which O(10 TeV) stop masses, typically required by the Higgs boson mass in supersymmetric models, do not originate from soft supersymmetry breaking terms that would drive the Higgs mass squared parameter to large…
A composite model of fermions is proposed to explain the "anomaly" in $Z \rightarrow b {\bar b}$ and, to a lesser extent, in $Z \rightarrow c {\bar c}$. It contains a {\em nonsequential} fourth family whose mass of one member (the charge…
The recently updated measurement of the $W$-boson mass by the CDF collaboration exhibits a $7\sigma$ deviation from the SM expectation, which may imply a sign of new physics beyond the SM. The observed discrepancy could be explained by new…
In this thesis we study top-condensation models of electroweak symmetry breaking. In particular we investigate a scenario in which the CP symmetry is broken spontaneously due to the same condensates responsible of electroweak symmetry…
If the gauge fields of the Standard Model propagate in TeV-size extra dimensions, they rapidly become strongly coupled and can form scalar bound states of quarks and leptons. If the quarks and leptons of the third generation propagate in 6…
Spontaneous breaking of inter-family (horizontal) gauge symmetries can be at the origin of the mass hierarchy between the fermion families. The corresponding gauge bosons have flavor-nondiagonal couplings which generically induce the…
We investigate the implications of models that achieve a Standard Model-like Higgs boson of mass near 125 GeV by introducing additional TeV-scale supermultiplets in the vector-like 10+\bar{10} representation of SU(5), within the context of…
In this talk, I shall address two key issues related to electroweak symmetry breaking. First, how fine-tuned different models are that trigger this phenomenon? Second, even if a light Higgs boson exists, does it have to be necessarily…
Prediction of low-mass $W_R$ and $Z_R$ gauge bosons in popular grand unified theories has been the subject of considerable attention over the last three decades. In this work we show that when gravity induced corrections due to dim.5…
Dynamical symmetry breaking provides a possible solution to the electroweak hierarchy problem. It requires new strong interactions that are effective at some high-energy scale. If there is no light Higgs boson, this scale is constrained to…
SU(2)xU(1) electroweak gauge model without Higgs sector is extended by a new vector field C interacting with leptons and quarks of both chiralities. This interaction is treated under a dynamical assumption in a self-consistent…
Assuming the existence of a supersymmetric U(1) gauge factor at the TeV energy scale (motivated either by the superstring-inspired E_6 model or low-energy electroweak phenomenology), several important consequences are presented. The…
We give an introduction to the dynamical symmetry breaking with large anomalous dimension. This is the basis of tightly bound composite Higgs models such as walking technicolor, strong ETC technicolor and top quark condensate, which are all…
At the TeV scale, heavy quarks, for example the 4th generation quarks of the Standard Model with four generations, can form condensates which dynamically break the electroweak symmetry. A dense quark system may form other types of…
We examine spontaneous symmetry breaking of a renormalisable U(1) x U(1) gauge theory coupled to fermions when kinetic mixing is present. We do not assume that the kinetic mixing parameter is small. A rotation plus scaling is used to remove…
A general framework is presented for supersymmetric theories that do not suffer from fine-tuning in electroweak symmetry breaking. Supersymmetry is dynamically broken at a scale \Lambda \approx (10 - 100) TeV, which is transmitted to the…
New results from the CDF Collaboration on the invariant mass distribution of dijet events observed at the Tevatron are used to constrain the masses and couplings of new gauge bosons ($W'$ and $Z'$) as well as fundamental diquarks which can…
A Higgs-like new boson with mass around 126 GeV is now established, but its true nature probably cannot be settled with 2011--2012 LHC data. We assume it is a dilaton with couplings weaker than the Higgs boson (except to $\gamma\gamma$ and…