Related papers: New Fermions at e$^+$e$^-$ Colliders: II.~Signals …
The anticipated physics program at an high energy e+e- linear collider places special emphasis on the accuracy in extrapolating charged particle tracks to their production vertex to tag heavy quarks and leptons. This paper reviews physics…
We calculate the cross sections for the single production of doubly-charged dileptons, both scalar and vector, at $e^+e^-$, $e\gamma$ and $\gamma\gamma$ colliders at $\sqrt{s}=500$ GeV and 1 TeV. The $e\gamma$ mode is by far the most…
It is very likely that in 3-4 years the construction of one or two linear colliders with c.m.s energy up to 0.5--1.5 TeV will be started. Besides e^+e^- collisions, linear colliders give a unique possibility to study gamma-gamma and…
If new particles are discovered, it will be important to determine if they are the supersymmetric partners of standard model bosons and fermions. Supersymmetry predicts relations among the couplings and masses of these particles. We discuss…
Preliminary results on $e^+ e^- \to f \bar{f}$, $f=e, \mu, \tau, q$, including all LEP2 data are discussed. Good agreement is found with the Standard Model up to the highest energies. Limits on possible new physics are extracted.
We investigate the production, backgrounds and signatures of pairs of charged heavy-fermions using the SU(3)$_L\otimesU(1)_N$ electroweak model in $e^+ e^-$ colliders (NLC and CLIC). We also analyze the indirect evidence for a boson…
At future e+- e- linear colliders, the event rates and clean signals of scalar fermion production - in particular for the scalar leptons - allow very precise measurements of their masses and couplings and the determination of their quantum…
We investigate the possibility of studying E$_6$ phenomenology at high energy hadron colliders. The production of heavy leptons pairs {\it via} a gluon-gluon fusion mechanism is discussed. An enhancement in the parton level cross-section is…
The physics program of high energy e+e- linear colliders relies on the accurate identification of fermions to study in details the profile of the Higgs boson, search for new particles and later probe the multi-TeV mass region by direct…
A search for excited lepton production in e+e- collisions was performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies ranging from 189 GeV to 209 GeV, corresponding to an integrated luminosity of…
If the gravitino G is very light and all the other supersymmetric particles are above threshold, supersymmetry may still be found at colliders, by looking at processes with only gravitinos and ordinary particles in the final state. We…
We study the pair production of right selectrons at a 500 GeV $e^-e^-$ collider followed by their decay into an electron and a lightest neutralino. This lightest neutralino decays into multifermion final states in the presence of…
As any $e^+e^-$ scattering process can be accompanied by a hard photon emission from the initial state radiation, the analysis of the energy spectrum and angular distributions of those photons can be used to search for hard processes with…
The status of four and six fermion event generators for Standard Model processes at present and future e^+e^- colliders is briefly reviewed.
Neutrinos are among the most mysterious particles in nature. Their mass hierarchy and oscillations, as well as their antiparticle properties, are being intensively studied in experiments around the world. Moreover, in many models of physics…
Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward…
The search for physics beyond the Standard Model motivates new high-energy accelerators, which will require high luminosities in order to produce interesting new heavy particles. Using the Higgs boson and supersymmetry as examples, we…
A high energy linear e^+e^- collider (LC) can also be used as a Photon Collider (PC), using Compton scattering of laser photons on the e^+/e^- beams. The leading order cross-section for the production of heavy quarks, e^+e^- -> e^+e^-…
We discuss the production of the doubly charged leptons in future linear electron positron colliders, such as the International Linear Collider and Compact Linear Collider. Such states are introduced in extended weak-isospin multiplets by…
A fermion can be chiral or vectorlike with respect to a given symmetry, depending on its coupling to the corresponding gauge boson. Vectorlike fermions have a distinct property that their left-handed and right-handed components behave in…