Related papers: Rare top quark decays in extended models
I present a mini-review on the physics of heavy flavour baryons where I concentrate on the HQET description of their exclusive decay modes. In particular I discuss the structure of current-induced bottom baryon to charm baryon transitions,…
A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay $\phi^0 \to t\bar{c}+\bar{t}c$, where $\phi^0$ could be a CP-even scalar ($H^0$) or a CP-odd pseudoscalar ($A^0$).…
We show that for a heavy vector-like quark model with a down type isosinglet, branching ratio for $c\rightarrow u\gamma$ decay is enhanced by more than $\mathcal{O}(10^2)$ as compared to that in the Standard model when QCD corrections to…
An analysis of charm mesons decaying semileptonically via Flavor Changing Neutral Currents is presented. We calculate the Wilson coefficients within the Standard Model. A window in the decay distribution, where physics beyond the Standard…
Top quark decays are of particular interest as a mean to test the standard model (SM) predictions, both for dominant (t -> b + W) and rare decays (t -> q + W, cV, cVV, c phi^{0}, bWZ). As the latter are highly suppressed, they become an…
Flavour-changing-neutral currents (FCNCs) involving the top quark are highly suppressed within the Standard Model (SM). Hence, any signal in current or planned future collider experiments would constitute a clear manifestation of physics…
We present a search for flavor changing neutral currents via quark-gluon couplings in a sample of single top quark final states corresponding to 2.3 fb^-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron…
A calculation of the one-loop contribution to the rare three-body flavor changing neutral current top quark decay $t\to c\gamma\gamma$ is presented in the framework of models with one or more scalar leptoquark $SU(2)$ doublets with…
Rare flavour-changing neutral-current transitions of the type $s \to d \ell^+\ell^-(\nu\bar\nu)$ and $b \to s \ell^+\ell^-(\nu\bar\nu)$ are analysed in supersymmetric extensions of the Standard Model with generic flavour couplings. It is…
If new physics (e.g. SUSY) does not show up as direct evidence at the LHC, it could still be observable in FCNC processes involving the $t$-quark. We take a close look at the process $t\to c + h/Z$ and show that its branching ratio in the…
The simplest extension of the SM that generally introduces new sources of flavour and CP violation as well as right-handed currents is the addition of a U(1) gauge symmetry to the SM gauge group. If the corresponding heavy gauge boson Z'…
Among other roles the LHC will play a role of the top "factory" and it will give us unique possibility to study new physics signatures in different ways. Many scenarios of new physics allow top quark FCNC decays. Using most general model…
Many extensions of the Standard Model(SM) generate contributions to Flavor Changing Neutral Current(FCNC) processes that must have sufficient flavor suppression to be consistent with experiments, if the new physics (NP) is associated with a…
The presence of the anomalous top quark flavour changing neutral current (FCNC) interactions leads to the production of same-sign top quarks in proton-proton collisions. The results of a search for events with same-sign dileptons and b-jets…
We consider Flavour Changing Neutral Current processes in the framework of the supersymmetric extension of the Standard Model. FCNC constraints on the structure of sfermion mass matrices are reviewed. Furthermore, we analyze supersymmetric…
The anomaly of the top quark forward-backward asymmetry $A^t_{FB}$ observed at the Tevatron can be explained by the t-channel exchange of a neutral gauge boson (Z') which has sizable flavor changing coupling for top and up quarks. This…
A search for flavour-changing neutral currents (FCNC) processes in proton-proton ($pp$) collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the CERN Large Hadron Collider (LHC) is presented. The analysed data…
The problem of possible deviations from the Standard Model is considered in the framework of a variant of dynamical electroweak symmetry breaking. It comes clear, that the parameters of the theory, being obtained earlier and describing…
In the present study, we investigate the decays of the top quark $t\rightarrow c\gamma$, $t\rightarrow cg$, $t\rightarrow cZ$ and $t\rightarrow ch$. They are extremely rare processes in the Standard Model (SM). As the $U(1)$ extension of…
We study the flavor changing neutral current couplings of new heavy quarks through the Z' models at the LHC. We calculate the cross sections for the signal and the corresponding standard model background processes. Considering the present…