Related papers: Loop Effects of Exotic Leptons on Vector-Boson Pai…
The production at the LHC of exotic excited leptons of charge $Q = +2e$ is considered. Such states are predicted in composite models with extended isospin multiplets ($I_{W}=1$ and $I_{W}=3/2$). The coupling among these doubly charged…
We present the full tree-order calculation of the process $e^+e^-\to\ell\bar{\nu}_\ell\; q \bqp$ including the width effects in a way which is consistent with gauge invariance and high energy unitarity and which has a natural interpretation…
Events stemming from the pair-production of Z bosons in e^+e^- collisions are studied using 217.4 pb^-1 of data collected with the L3 detector at centre-of-mass energies from 200 GeV up to 209 GeV. The special case of events with b quarks…
We present a model-independent description of the exclusive rare decays B-> K* e+e- in the low recoil region (large lepton invariant mass q^2 ~ m_b^2). In this region the long-distance effects from quark loops can be computed with the help…
We point out that in a large class of superstring--inspired $E(6)$ models, either an e+e- collider operating at a center--of--mass energy $\rs= 1.5$ TeV or higher must detect the pair production of charged or neutral exotic leptons, or an…
We present a comprehensive study of Higgs boson production associated with a neutrino pair at $e^+e^-$ colliders ($e^+ e^- \to h \, \nu \bar{\nu}$) at next-to-leading-order accuracy in both the Standard Model and the two-Higgs-doublet…
We discuss exclusive production of lepton-antilepton, quark-antiquark, $\pi \pi$ and $\rho^0 \rho^0$ pairs in ultraperipheral, ultrarelativistic heavy-ion collisions. The cross sections for exclusive production of pairs of particles is…
The precise investigation of the $W^+ W^-Z^0$ production at the $e^+e^-$ International Linear Collider(ILC) is of crucial importance in probing the couplings between massive vector gauge bosons and discovering the signature of new physics…
Generation dependent discrete symmetries often appear in models derived from superstring theories. In particular, in the framework of E$_6$ models the presence of such symmetries is required in order to allow for the radiative generation of…
We consider the production at the LHC of exotic composite quarks of charge $Q=+(5/3) e$ and $Q=-(4/3) e$. Such states are predicted in composite models of higher isospin multiplets ($I_W=1$ or $I_W=3/2$). Given their exotic charges (such as…
This work explores the discovery potential of the first-generation weak isosinglet Vector-Like Leptons (VLLs), denoted by $E^\pm$, via pair production at future electron-positron colliders. Our analysis adopts a comprehensive framework that…
Doubly charged excited leptons give rise to interesting signatures for physics beyond the standard model at the present Large Hadron Collider. These exotic states are introduced in extended isospin multiplets which couple to the ordinary…
We perform a comprehensive and model-independent analysis for characterizing the spin and dynamical structure of the production of a non-diagonal pair of Majorana particles with different masses and arbitrary spins, $e^-e^+\to X_2 X_1$,…
In this review phenomenological consequences of the Standard Model extension by means of new spin-1 chiral fields with the internal quantum numbers of the electroweak Higgs doublets are summarized. The prospects for resonance production and…
We investigate the production and signatures of a single, pair of heavy-exotic leptons via the electron-positron induced process and a pair of heavy exotic leptons via the Drell-Yan process at the CERN Large Hadron Collider (LHC). We show…
In this letter we analyze the associated production of a vector meson with the bound - free $e^+e^-$ process in ultraperipheral $PbPb$ collisions through the double scattering mechanism for the energy of the Large Hadron Collider (LHC).…
We study the process $e^- + e^+ \to e^+ + e^+ + e^- + e^-$ for ILC and CLIC energy regimes, in the minimal 3-3-1 model framework. The main contributions, for the production of two bileptons each one decaying into two same-sign leptons, come…
In light of the ongoing effort on reducing the theoretical uncertainties and an upcoming experiment concerning muon magnetic moment, we perform a detailed study of an 3-4-1 electroweak gauge extension of the standard model that contains…
We analyse the loop induced production of Higgs boson pairs at future high--energy $e^+e^-$ colliders, both in the Standard Model and in its minimal supersymmetric extension. The cross sections for Standard Model Higgs pair production…
We consider the possibility of fingerprinting the presence of heavy additional Z' bosons that arise naturally in extensions of the standard model such as E_6 models and left-right symmetric models, through their mixing with the standard…