Related papers: Top flavour-changing neutral coupling signals at a…
We consider a general effective Lagrangian for couplings of a Higgs boson to the top-quark to dimension-six operators including CP violation effects. Constraints on some of them are derived from the $Z\to b\bar b$ data. We study the process…
The prospect of observing the flavor changing decay $\fH\to t\bar c$ of a neutral Higgs boson produced via $s$-channel and its subsequent decay into $t\bar c$ is considered at a $\mu^+\mu^-$ collider. Numerical estimates are given in the…
The reactions e+e- -> t bar-c nu_e bar-nu_e, t bar-c e+ e- are very sensitive probes of the flavor-changing-scalar couplings which can occur in a model with one extra Higgs doublet. At the Next Linear Collider, with a center of mass energy…
We perform the comprehensive analysis of the polarization effects on the e^+e^- -> W^+W^- process in the presence of the extra neutral gauge boson at the LC energies. Consideration of the polarizations of the produced W bosons and the beam…
In the context of topcolor-assisted techicolor($TC2$) models, we investigate the feasibility of detecting the non-universal gauge boson $Z^{'}$ in the future high-energy linear $e^{+}e^{-}$ collider($LC$) experiments by performing…
The Standard Model (SM) has no flavor-changing neutral current (FCNC) processes at the tree level. Therefore, processes featuring FCNC in new physics are tightly constrained by data. Typically, the lower bounds on the scale of new physics…
A search for flavour-changing neutral current (FCNC) processes in top-quark decays is presented. Data collected from proton-proton collisions at the LHC at a centre-of-mass energy of $\sqrt{s}=13$ TeV corresponding to an integrated…
We present the sensitivity to Flavor Changing Neutral Currents (FCNC) in interactions involving the top quark at future $e^+e^-$ and $\mu^+\mu^-$ machines. We consider the $Ztc$ vertex as well as four-fermion contact interactions involving…
The search for lepton flavor violation (LFV) is a powerful probe to look for new physics beyond the Standard Model. We explored the possibility of searches for LFV $Z$ boson couplings to electron and muon pairs at the upcoming…
We examine the contributions of various couplings in general ZZH and gammaZH interactions arising from new physics to the Higgs production process e+e- --> HZ, followed by the decay of the Z into a charged-lepton pair. We take into account…
Extra neutral gauge bosons arise in many extensions of the Standard Model. If one were to be discovered it would be necessary to measure its properties so that we could understand its origins. In this report we find that Z' couplings can be…
We study the sensitivity of top pair production at the Large Hadron Collider (LHC) to the nature of an underlying Z' boson, including full tree level standard model background effects and interferences. We demonstrate that exploiting…
We investigate flavor-changing neutral current (FCNC) interactions of the top quark at a future muon collider with a center-of-mass energy of $\sqrt{s} = 10~\mathrm{TeV}$. The process $\mu^{+}\mu^{-} \to \nu_{\mu}\,\mu^+\,b\,j$ and its…
We investigate the sensitivity to new physics of the process e+e- -> t bar{t} when the top polarization is analyzed using leptonic final states e+e- -> t \bar{t} -> l+l- b \bar{b} nu_l \bar{nu}_l. We first show that the kinematical…
A strong candidate for the Standard Model Scalar boson, H(126), has been discovered by the Large Hadron Collider (LHC) experiments. In order to study this fundamental particle with unprecedented precision, and to perform precision tests of…
A search is presented for flavour-changing neutral-current interactions involving the top quark, the Higgs boson and an up-type quark ($q=u,c$) with the ATLAS detector at the Large Hadron Collider. The analysis considers leptonic decays of…
Our main aim in this paper is to present detailed studies to probe the top quark flavor changing neutral current (FCNC) interactions at $tqg$, $tq\gamma$, $tqH$ and $tqZ (\sigma^{\mu \nu}, \gamma_{\mu})$ vertices in the triple-top signal $p…
It was reported that the NNLO correction to the total cross section near the ttbar threshold in e+e- collisions is as large as the NLO correction to it. In the thesis, we improve the convergence of the perturbative series of the total cross…
A search for flavour-changing neutral current decays of a top quark to an up-type quark ($q=u, c$) and the Standard Model Higgs boson, where the Higgs boson decays to $b\bar{b}$, is presented. The analysis searches for top quark pair events…
TeV-scale $Z^\prime$ bosons with family-dependent couplings can explain some anomalies inferred from $B-$meson measurements of processes involving the $b \rightarrow s \ell^+\ell^-$ transition. A $Z^\prime$ originating from…