Related papers: Top quark induced vacuum misalignment in little hi…
In grand unified theories (GUT) based on SO(10) all fermions of one generation are embedded in a single representation. As a result, the top quark, the bottom quark, and the $\tau$ lepton have a universal Yukawa coupling at the GUT scale.…
We present the study of the quark sector of the universal seesaw model with $\mathrm{SU(2)_L \times SU(2)_R \times U(1)_{Y'}}$ gauge symmetry in the massless case of the two lightest quark families. This model aims to explain the mass…
A primary goal of present and future colliders is measuring the Higgs couplings to Standard Model (SM) particles. Any observed deviation from the SM predictions for these couplings is a sign of new physics whose energy scale can be bounded…
I describe, from the bottom up, a sequence of natural effective field theories. Below a TeV we have the minimal standard model with a light Higgs, and an extra neutral scalar. In the 1-10 TeV region these scalars are part of a multiplet of…
We explore the gauge hierarchy problem within the framework of supersymmetric $SU(3)_c \times SU(3)_L \times SU(3)_R$ with a minimal set of higgs supermultiplets. Imposition of a suitable discrete (alternatively $R$) symmetry `prevents' the…
With the deeper study of Higgs particle, Higgs precision measurements can be served to probe new physics indirectly. In many new physics models, vector-like quarks $T_L,~T_R$ occur naturally. It is important to probe their couplings with…
We systematically construct flipped SU(5) X U(1)_X models without and with bulk vector-like particles from F-theory. To realize the decoupling scenario, we introduce sets of vector-like particles in complete SU(5) X U(1) multiplets at the…
In the context of the Minimal Supersymmetric extension of the Standard Model, I discuss the effects of relatively light top and bottom scalar quarks on the main production mechanism of the lightest SUSY neutral Higgs boson $h$ at the LHC,…
From the tau-lepton analysis of the charged Higgs decay of the top quark at the Tevatron, t -> H+ b -> tau+ nu_{tau} b, it is possible to set rather stringent bounds on the (tan(beta),M_{H+})-plane, if one assumes that H+ is a charged…
A toy model giving rise to long lived super heavy particles and an small vacuum density energy, of the order of the one measured in the present universe, is constructed. This model consists in hidden sector invariant under an $SU(2)_L$…
We show that by combining the elementary-Goldstone-Higgs scenario and supersymmetry it is possible to raise the scale of supersymmetry breaking to several TeVs by relating it to the spontaneous-symmetry-breaking one. This is achieved by…
Models with massive vector leptoquarks, resulting from an $SU(4)$ gauge symmetry spontaneously broken at the TeV scale, are of great phenomenological interest given the current "anomalies" in semileptonic $B$ decays. We analyze the…
Top quarks produced in pairs are predicted to experience spin correlations. Due to the large ttbar statistics expected for the LHC, it should be possible to search for new physics effects in angular variables sensitive to these…
Top quark with its large Yukawa coupling is crucially important to explore TeV scale physics. Therefore, the study of Higgs-top sector is highly motivated to look for any deviations from the standard model predictions. The most general…
We present a model of electroweak symmetry breaking in which the Higgs boson is a pseudo-Nambu-Goldstone boson. By embedding the standard model SU(2) x U(1) into an SU(4) x U(1) gauge group, one-loop quadratic divergences to the Higgs mass…
We derive lower bounds for the Higgs-curvature coupling from vacuum stability during inflation in three inflationary models: quadratic and quartic chaotic inflation, and Starobinsky-like power-law inflation. In contrast to most previous…
We investigate the corrections of the littlest Higgs(LH) model and the SU(3) simple group model to single top production at the CERN Large Hardon Collider(LHC). We find that the new gauge bosons $W_{H}^{\pm}$ predicted by the LH model can…
We study the phenomenology of charged Higgs bosons ($H^\pm$) and Vector-Like Quarks (VLQs), denoted as $T$, the latter possessing a charge identical to the top quark one, within the framework of the Two Higgs Doublet Model Type-II…
The supersymmetric decays of the top quark into charged Higgs plus bottom, $\thb$, and into the supersymmetric partner of the top (${\wti u}_1$) plus the lightest neutralino (${\wti \chi}_1^0$), $\tstopneu$, are discussed within the…
It is challenging for supersymmetry if the 125 GeV Higgs boson is confirmed by the LHC. In the case of small squark mixing it is inevitable to introduce heavy top squarks to lift the Higgs mass that is hard to be produced by the LHC. Here…