Related papers: Effective operators in top physics
We extend the standard top-quark Yukawa coupling with a dimension-6 operator in order to accommodate a CP violating complex phase with manifest gauge invariance. This leads to a new $ttHH$ contact interaction, along with many Goldstone…
We consider renormalisable models extended in the scalar sector by a generic scalar field in addition to the standard model Higgs boson field, and work out the effective theory for the latter in the decoupling limit. We match the full…
We derive bounds on Higgs and gauge--boson anomalous interactions using the LEP2 data on the production of three photons and photon pairs in association with hadrons. In the framework of $SU(2)_L \otimes U(1)_Y$ effective Lagrangians, we…
The aim of this thesis is to determine possible interactions between the Standard Model with right-chiral neutrinos and a sector of dark matter composed of a real scalar, left- and right-chiral fermion and a vector particle, which are…
We probe the dimension-six operators contributing to Higgs production in association with a $Z$ boson at the future high-luminosity electron-positron colliders. Potential constraints on dimension-six operators in the Higgs sector are…
For a light enough Higgs boson, the effective potential of the Standard Model develops a dangerous instability at some high energy scale, Lambda, signalling the need for new physics below that scale. On the other hand, a typical low-energy…
We study the effects of dimension-six operators contributing to the $gt\bar t$ vertex in top quark pair production at the Tevatron collider. We derive both the limits from Run 1 data and the potential bounds from future runs (Run 2 and 3).…
We compute the one-loop renormalisation group running of the bosonic Standard Model effective operators to order $v^4/\Lambda^4$, with $v\sim 246$ GeV being the electroweak scale and $\Lambda$ the unknown new physics threshold. We…
We study gravity with torsion in extra dimensions and derive an effective four-dimensional theory containing four-fermion contact operators at the fundamental scale of quantum gravity in the TeV range. These operators may have an impact on…
We have analysed the observable consequences of the interactions of spin-1 resonances coupled to the invariant fermionic currents that arise in an $SO(5)$ Composite Higgs set-up. The phenomenology entailed by such interactions is thoroughly…
Meson-antimeson mixing provides the most stringent constraints on baryon- and lepton-number conserving New Physics, probing scales higher than $10^5$ TeV. In the context of the effective theory of weak interactions, these constraints…
We explore a scenario in the Standard Model in which dimension four Yukawa couplings are either forbidden by a symmetry, or happen to be very tiny, and the Yukawa interactions are dominated by effective dimension six interactions. In this…
We study in the effective Lagrangian approach the possibility of probing anomalous top quark charged current couplings in the single top production at a high energy e\gamma collider. We analyzed all possible dimension-six CP-conserving…
We consider models that generate hierarchies via the separation of fermion wavefunctions in higher-dimensional spaces. We calculate the effects of gauge interactions between fermions and show that these are important and could help to…
We consider the observable effects of CP-violating anomalous $ZZh$ interaction arising from gauge invariant dimension-6 operators at the Large Hadron Collider (LHC), with the purpose of distinguishing them from not only the standard model…
The standard-model can be equivalently represented with its fields in a spin-extended basis, departing from fermion degrees of freedom. The common Higgs operator connects the electroweak and Yukawa sectors, restricting the top and bottom…
There is growing interest in the development of a muon collider that would make it possible to produce lepton collisions at energies of several TeV. Among others, there can be significant contributions to electroweak gauge boson, Higgs…
We study whether higher-dimensional operators in effective field theories, in particular in the Standard Model Effective Field Theory (SMEFT), can source gauge anomalies via the modification of the interactions involved in triangle…
We study anomalous gauge-boson couplings induced by a locally SU(2) x U(1) invariant effective Lagrangian containing ten operators of dimension six built from the boson fields of the Standard Model (SM) before spontaneous symmetry breaking…
The unified compositeness of leptons, quarks and Higgs bosons is proposed as a possible scenario for New Physics beyond the Standard Model. The following topics of the scenario are briefly discussed: - Chiral gauge exceptional symmetry E_6…