Related papers: The Top Quark Decay Vertex in Standard Model Exten…
As the Higgs boson properties settle, the constraints on the Standard Model extensions tighten. We consider all possible new fermions that can couple to the Higgs, inspecting sets of up to four chiral multiplets. We confront them with…
We review the effects of new effective interactions on the Higgs boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge…
I discuss how modified EW interactions lead to energy growth in $2\to 2$ scattering amplitudes and how the framework of the Standard Model Effective Field Theory can be used in conjunction with the Goldstone boson equivalence theorem to…
We examine flavour-changing neutral-current decays of the top quark, $t\to q \gamma$, $t \to qZ$, $t \to q H$, and $ t\to q g$ (with $q=u, c$), in the Alternative Left-Right Model, a left right-symmetric model featuring exotic quarks and…
The standard model(SM) predicts only a $g_{V-A}$ coupling in $t \to W^+ b$ decay. However, if additional Lorentz structures exist, they can manifest themselves in high energy processes such as this via non-SM values of the helicity…
Anomalous chromomagnetic and chromoelectric dipole moments of the top quark may arise from various high scale theories. We carry out a model independent study of such interactions focusing on the limits that can be obtained from current…
We investigate the anomalous interactions of heavy up-type quark t' in a $\gamma \gamma$ collision at the LHC. We have obtained 95% confidence level(CL)limit of $t'q \gamma$ anomalous coupling by taking into account three forward detector…
In the simplest examples of models with a discrete quark-lepton symmetry, an electroweak symmetry breaking sector with more than one Higgs doublet is necessary to obtain the correct mass relations between quarks and leptons. A two Higgs…
The Standard Model provides an excellent description of the observables measured at high energy lepton and hadron colliders. However, measurements of the forward-backward asymmetry of the bottom quark at LEP suggest that the effective…
The top quark decay process $\tcups$ is studied in the Standard Model and the Minimal Supersymmetric Standard Model with conserved and violated $R-$parity. In dealing with the heavy quarkonium, $\ups$, production, we take both color-singlet…
$\cal T$-parity in the Little Higgs model could be violated by anomalies that allow the lightest $\cal T$-odd $A_H$ to decay into $ZZ$ and $W^+W^-$. We analyze these anomaly induced decays and the two-particle and the three-particle decay…
Chromomagnetic and chromoelectric dipole interactions of the top quark are studied in a model independent framework. Limits are set on the scale of new physics that might lead to such contributions using available Tevatron data. Prospects…
The invisible variant axion model is very attractive as it is free from the domain wall problem. This model requires at least two Higgs doublets at the electroweak scale, with one Higgs doublet carrying a nonzero Peccei-Quinn (PQ) charge…
For the " t --> W b " decay mode, an intensity-ratio equivalence-theorem for two Lorentz-invariant couplings is shown to be related to symmetries of tWb-transformations. Explicit tWb-transformations, A_{+}=M A_{SM}, P A_{SM}, B A_{SM}…
We have investigated the flavor changing top quark physics on the dimension-six anomalous $tq\gamma$ ($q=u,c$) couplings through the process $pp\to p\gamma \gamma p\to p t\bar{q}p$ at the LHC by considering different forward detector…
Extensions of the Standard Model that include vector-like quarks commonly also include additional particles that may mediate new production or decay modes. Using as example the minimal linear $\sigma$ model, that reduces to the minimal…
The ATLAS potential for the study of the top quark properties and physics beyond the Standard Model in the top quark sector, is described. The measurements of the top quark charge, the spin and spin correlations, the Standard Model decay…
Several extensions of the Standard Model require the burden of electroweak symmetry breaking to be shared by multiple states or sectors. This leads to the possibility of the top quark interacting with a scalar more strongly than it does…
The ATLAS and CMS collaborations observed a mild excess in the associated Higgs production with a top-quark pair ($t\bar t h$) and reported the signal strengths of $ \mu_{tth}^{\rm ATLAS}=1.81\pm 0.80$ and $\mu_{tth}^{\rm CMS}=2.75\pm 0.99…
An analysis is given of the dynamical symmetry breaking of semi-simple gauge groups. We construct a class of renormalizable gauge theories for the dynamically broken topcolor and technicolor interactions. It is shown that a four-Fermi…