Related papers: Testing a Model with extra Vector Fermions at the …
We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair…
Hints of lepton flavor violation have been observed by LHCb in the rate of the decay $B\to K\mu^+\mu^-$ relative to that of $B\to K e^+e^-$. This can be explained by new scalars and fermions which couple to standard model particles and…
Many models of Beyond the Standard Model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In…
A high energy muon collider can provide new and complementary discovery potential to the LHC or future hadron colliders. Leptoquarks are a motivated class of exotic new physics models, with distinct production channels at hadron and lepton…
The extension of the Standard Model with exotic quark singlets and doublets introduces large flavor changing neutral couplings between ordinary fermions. We derive inequalities which translate the precise determination of the diagonal Z…
We propose a model with two Higgs doublets and several $SU(2)$ scalar singlets with a global non-Abelian flavor symmetry $\mathcal{Q}_6\times\mathcal{Z}_2$. This discrete group accounts for the observed pattern of fermion masses and mixing…
The LHCb Collaboration recently gave an update on testing lepton flavour universality with $B^+ \rightarrow K^+ \ell^+ \ell^-$, in which a 3.1 standard deviations from the standard model prediction was observed. The g-2 experiment also…
We propose a way to differentiate between various extra $U(1)$ models using flavor tagging in the decay modes $Z^{\prime}\rightarrow q{\bar{q}}$ once the extra $Z^{\prime}$ is observed at future colliders in the lepton channel. A…
Searches for physics beyond the Standard Model have been performed in high-energy $e^{\pm}p$ collisions at HERA. No significant deviation from the Standard Model has been observed while searching for contact interactions, extra dimensions,…
The updated analysis of the LHCb Collaboration on the lepton flavor violation suggests that the new physics should couple to muons and electrons with comparable magnitudes, resulting in the anomalies in both rare decay channels, $b…
We present a measurement of the ttbar production cross section using events with one charged lepton and jets from ppbar collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are…
Observed neutrino oscillations imply that the global lepton flavor symmetry of the Standard Model must be broken. Therefore, searches for lepton flavor violation (LFV) are promising probes of new physics beyond the Standard Model.…
We make a comprehensive study of vector-like fermionic dark matter and flavor anomalies in a simple extension of standard model. The model is added with doublet vector-like fermions of quark and lepton types, and also a…
There is a strong experimental program searching for massive sterile neutrinos. Here we focus on the heavy regime above the GeV scale, where their existence can be probed in either high-energy colliders or in high-precision facilities. We…
We study the properties of vectorlike fermions that have the same gauge charges as the Standard Model lepton doublets, but opposite lepton number. These antileptons undergo decays mediated by heavier scalar leptoquarks, while the symmetries…
We discuss the possibility of explaining the excess in the cross section at high-Q^2 recently found at HERA in terms of four-fermion effective interactions. To avoid the constraints from low-energy data, we select three special cases in…
Recent results on searches for physics beyond the Standard Model obtained by the H1 and ZEUS experiments are reported here. After a brief introduction to the HERA collider, indirect searches for contact interactions and extra-dimensions are…
The associated production of $Z$ boson and a pair of new quarks at the Large Hadron Collider (LHC) is studied. The cross sections for both sequential fermions and vector-like fermions are presented. It is found that for sequential fermions…
We propose two minimal extensions of Standard Model, both of which can easily accommodate the recent puzzling observations about the excess in $R_b$, the deficit in $R_c$ and the discrepancy in the low energy and high energy determinations…
In this paper, the possibility to have new physics is considered at the scale of the electroweak symmetry breaking (EWSB) in a completely new framework. A new non-standard minimal chiral fermion extension of the Standard Model (SM) which…