In this work, we investigated resonant production of spin-3/2 color octet electron at the Large Hadron electron Collider (LHeC). Signal and background analysis have been performed and discovery, observation and exclusion limits are determined for spi
n 3/2 color octet electron masses. Reachable values of the compositeness scale are presented as a function of the spin-3/2 color octet electron masses.
In this work we consider pair production of LSP tau-sneutrinos at the Compact Lineer Collider. We assume that tau-sneutrinos decays in to etextmu pair via RPV interactions. Backgroundless subprocess $e{}^{-}e^{+}rightarrowtilde{ u}bar{tilde{ u}}right
arrowmu^{+}mu^{+}e^{-}e^{-}(mu^{-}mu^{-}e^{+}e^{+})$ is analyzed in details. Achievable limits on $Br,(tilde{ u}_{tau}rightarrowmu e)$ at $3sigma$ and $5sigma$ CL are obtained depending on $tilde{ u_{tau}}$ mass.
In a recent Letter Martinez et al.2011 have argued that the existence of extra three families is still perfectly in accord with the standard model (SM), as long as an additional Higgs doublet is also present. Here we claim that the mentioned accordan
ce can be obtained with less reliance on BSM physics like additional Higgs doublets, but benefiting from Majorana neutrinos is sufficient.
We study the possible dynamics associated with leptonic charge in future linear colliders. Leptophilic massive vector boson, Z_(l), have been investigated through the process e^(+)e^(-) -> mu^(+)mu^(-). We have shown that ILC and CLIC will give oppor
tunity to observe Z_(l) with masses up to the center of mass energy if the corresponding coupling constant g_(l) exceeds 10^(-3).
Existence of the fourth family follows from the basics of the Standard Model and the actual mass spectrum of the third family fermions. We discuss possible manifestations of the fourth SM family at existing and future colliders. The LHC and Tevatron
potentials to discover the fourth SM family have been compared. The scenario with dominance of the anomalous decay modes of the fourth family quarks has been considered in details.
