Related papers: Distinguishing nonstandard scalar and fermionic ch…
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…
Fermion compositeness, and other types of new physics that can be described by the exchange of very massive particles, can manifest themselves as the result of an effective four-fermion contact interaction. In the case of the processes…
We explore models where single new exotic states interact with the Standard Model through an asymmetric Standard Model portal with couplings to at least one quark and one lepton. All effective operators up to dimension six where such…
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…
The past ten years of physics with e+e- colliding experiments at LEP and SLAC have shown the success of these experiments on not only impressively proving the theoretical predictions of the Standard Model (SM), but also to help provide…
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 investigate the prospects for detecting and measuring the parameters of WIMP dark matter in a model independent way at the International Linear Collider. The signal under study is direct WIMP pair production with associated initial state…
Extra neutral gauge bosons suggested by models beyond the standard model can indirectly show up in $e^{+} e^{-}$ collisions through off-resonance deviations of various physical observables from the corresponding standard model values. We…
Heavy neutral gauge bosons, Z's, are predicted by many theoretical schemes of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible…
We consider the production and decay of selectrons and charginos in $e^-e^-$ collisions. The advantage over usual $e^+e^-$ collisions is the very low level of standard model backgrounds which should make the discovery of selectrons or…
The present contribution reports a study of the effects of anomalous gauge and fermionic couplings in the process $e^+e^- -> W^+W^-$ at the Next Linear Collider focusing in particular on the option of polarized beams. We conclude that…
We study the potential of the next-generation $e^+ e^-$ linear colliders with longitudinally polarized beams, to restrict the values of the anomalous trilinear couplings $WW\gamma$ and $WWZ$ from the measurement of the process $e^+ e^-\to…
In the Standard Model, chiral electroweak anomalies predict nonperturbative interactions that violate baryon ($B$) plus lepton number ($L$). The potential observability of these processes at colliders has been amply discussed in the…
We approach the issue of the discovery of new physics at high energies associated with the proposed International Linear Collider in the presence of longitudinal as well as transverse electron and positron beam polarization. We determine…
Possible oblique effects from vector particles that are strongly coupled to the known gauge bosons are calculated for the case of final hadronic states produced at future $e^+e^-$ colliders, using a formalism that was recently proposed and…
We discuss the sensitivity to four-fermion contact interactions of the process of fermion-pair production at the e^+ - e^- Linear Collider (LC), with E_{CM}=0.5 TeV and longitudinally polarized electron beam. The analysis is based on…
Discovery of unexpected properties of the Higgs boson offers an intriguing opportunity of shedding light on some of the most profound puzzles in particle physics. The Beyond Standard Model (BSM) decays of the Higgs boson could reveal new…
The anomalous magnetic (MDM) and electric (EDM) dipole moments of the $\tau$ lepton serve as crucial indicators of new physics beyond the Standard Model. Leveraging azimuthal angular asymmetry as a novel tool in ultraperipheral collisions…
Many extensions of the standard model predict the existence of extra neutral vector bosons, generically referred as $Z^\prime$. This boson may be discovered at the LHC but in this case it will be necessary to study the respective parameters…
We show that measurements of single transverse-spin asymmetries at an $e^+e^-$ collider can enhance the sensitivity to the electron Yukawa coupling, possibly enabling observation of the Standard Model value for this quantity. We demonstrate…