Related papers: The Leptoquark Implication from the CMS and IceCub…
An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying $\tau$ leptons, is presented. The analysis is based on a data sample…
Recent observations by IceCube, notably two PeV cascades accompanied by events at energies ~ (30-400) TeV, are clearly in excess over atmospheric background fluxes and beg for an astroparticle physics explanation. Although some models of…
B-Physics anomalies have recently raised renewed interest in leptoquarks (LQ), predicted in several theoretical frameworks. Under simplifying but conservative assumptions, we show that the current limits from LHC searches together with the…
The t-channel exchange of a first generation leptoquark could contribute to the cross-section for q q-bar to e+e-. The leptoquark is off-shell, so this process can be sensitive to leptoquarks beyond the mass reach of pair production…
IceCube collaboration has published two papers on ultrahigh energy neutrinos observation, recently. They have used the data collected in two years in their first publication, which reveals observation of two PeV energy neutrino events. The…
While most studies of the minimal type-I seesaw neglect the heaviest decoupled right-handed neutrino, assuming negligible contributions to neutrino masses and leptogenesis, we demonstrate that its cosmological role can be significant. When…
We consider implications of the IceCube excess for hadronuclear (pp) scenarios of neutrino sources such as galaxy clusters/groups and star-forming galaxies. Since the observed neutrino flux is comparable to the diffuse gamma-ray background…
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…
The scale of neutrino masses and the Planck scale are separated by more than twenty-seven order of magnitudes. However, they can be linked by imposing the stability of the electroweak (EW) vacuum. The crucial ingredient is provided by the…
A recent study [1] has shown that a simplified model predicting a heavy scalar of mass 270 GeV ($H$) that decays to a Standard Model (SM) Higgs boson in association with a scalar singlet of mass 150 GeV ($S$) can accommodate several…
By introducing a set of new triplet leptons (with nonzero hypercharge) that can Yukawa couple to their Standard Model counterparts, new sources of tree-level flavor changing currents are induced via mixing. In this work, we study some of…
We construct a model of quark-lepton unification at the TeV scale based on an $SU(4)$ gauge symmetry, while still having acceptable neutrino masses and enough suppression in flavor changing neutral currents. An approximate $U(2)$ flavor…
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…
A search for first generation scalar and vector leptoquarks (LQ) as well as for squarks in R-parity violating SUSY models has been performed using e+e- collisions collected with the OPAL detector at LEP at an e+e- centre-of-mass energy…
Large Hadron Collider (LHC) has provided direct evidence of Yukawa couplings between the third generation charged fermions and the 125 GeV Higgs boson. Whether the first two generation charged fermions arise from exactly the same mechanism…
IceCube have observed neutrinos which are presumably of extra-galactic origin. Since specific sources have not yet been identified, we discuss what could be learned from the conceptual point of view. We use a simple model for neutrino…
We perform a detailed analysis of lepton flavour violation (LFV) within minimal see-saw type extensions of the Standard Model (SM), which give a viable mechanism of neutrino mass generation and provide new particle content at the…
Motivated by the disagreement between the experimental data and lattice calculations on the decay constant of the $D_{s}$ meson, we investigate leptoquark (LQ) contributions to the purely leptonic decays of a pseudoscalar (P). We…
We introduce two scalar leptoquarks, the SU$(2)_L$ isosinglet denoted $\phi\sim(\mathbf{3}, \mathbf{1}, -1/3)$ and the isotriplet $\varphi\sim(\mathbf{3}, \mathbf{3}, -1/3)$, to explain observed deviations from the standard model in…
We revisit a scenario with an enhanced top yukawa coupling in vector-like quark (VLQ) models, where the top yukawa coupling is larger than the standard model value and the lightest VLQ has a negative yukawa coupling. We find that the…