Related papers: Limits on Anomalous Top Couplings from Z Pole Phys…
We study top quark pair production in association with a Z boson at the Large Hadron Collider (LHC) and investigate the prospects of measuring the couplings of top quarks to the Z boson. To date these couplings have not been constrained in…
We study the T odd correlations induced by CP violating anomalous top-quark couplings at both production and decay level in the process gg --> t t_bar --> (b mu+ nu_mu) (b_bar mu- nu_mu_bar). We consider several counting asymmetries at the…
The top quark flavor changing neutral current processes are extremely suppressed within the Standard Model. Nevertheless, they could be enhanced in a new physics model beyond the Standard Model. Investigating the top quark's flavor changing…
We present a quantitative study on sensitivities to the top-decay anomalous couplings, taking into account realistic experimental conditions expected at Tevatron and LHC. A double angular distribution of W and charged lepton in the top…
Lepton and quark asymmetries at Z boson peak are a powerful means to test the couplings of the Z boson to fermions. The measurements performed at LEP and SLC colliders are reviewed, and their impact on the determination of the electroweak…
While $CP$ violation has never been observed in the strong interactions, the QCD Lagrangian admits a $CP$-odd topological interaction proportional to the so called $\theta$ angle, which weighs the contributions to the partition function…
In this work, we study the new physics effects arising due the presence of anomalous $Wtb$ vertex through the semileptonic decay modes of the top-quark at the Large Hadron Collider. An estimate on the sensitivities of the aforementioned…
It is possible to place constraints on non-Standard-Model gauge-boson self-couplings and other new physics by studying their one-loop contributions to precisely measured observables. We extend previous analyses which constrain such…
We discuss direct and indirect probes of chirality-flipping couplings of the top quark to Higgs and gauge bosons, considering both CP-conserving and CP-violating observables, in the framework of the Standard Model effective field theory. In…
We present new direct constraints on a general $Wtb$ interaction using data corresponding to an integrated luminosity of 5.4 fb$^{-1}$ collected by the D0 detector at the Tevatron $p\bar{p}$ collider. The standard model provides a purely…
Observation of top quark flavor changing neutral process $t\to c +\gamma$ at the LHC would be the signal of physics beyond the Standard Model. If anomalous $t\to c\gamma$ coupling exists, it will affect the precisely measured…
We investigate the possibility that an imaginary anomalous $tbW$ coupling can be measured in the process $e^-p \to \nu_e \overline t X$ by means of T-odd observables. One such observable considered here is the polarization of the top…
We study possible theoretical deviations from SM in top quark physics which alter the decay properties of the top quark. Using effective filed theory techniques we parametrize the effects of potential NP of scales well above the electroweak…
We analyse some dimension-five CPT-even and Lorentz-violating nonminimal couplings between fermionic and gauge fields in the context of the Dirac equation. After evaluating the nonrelativistic Hamiltonian, we discuss the behavior of the…
The bottom quark forward-backward asymmetry ($A_{FB}^b$) data at LEP exhibits a long-standing discrepancy with the standard model prediction. We propose a novel method to probe the $Zb\bar{b}$ interactions through $gg\to Zh$ production at…
The model (Lagrangian) with a peculiar extra U(1)is clearly presented. The assigned extra U(1) gauge charges give a strong constraint to build Lagrangians. The Z' discovery limits are estimated and predicted at the Tevatron and the LHC. The…
We calculate the CP-violating electric and weak dipole form factors of the top quark and the tau lepton in models with scalar leptoquarks coupling only to the third generation of quarks and leptons. We obtain numerical values of the real…
We obtain the partial-wave unitarity constraints on the lowest-dimension effective operators which generate anomalous quartic gauge couplings but leave the triple gauge couplings unaffected. We consider operator expansions with linear and…
We study effects of beyond the Standard Model physics coupling third generation quarks to leptons of the first two generations. We parametrize these effects by dimension-six effective operators, and we also consider related simplified UV…
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…