Related papers: Chargino Pair Production in $e^+e^-$ Collisions
Recently N. Arkani-Hamed and S. Dimopoulos proposed a supersymmetric model \cite{Arkani-Hamed:2004fb}, dubbed "Split Supersymmetry" in Ref. \cite{Giudice:2004tc}, which can remove most of the unpleasant shortcomings of TeV Supersymmetry. In…
We study polarization and spin correlation effects in the MSSM and in extended supersymmetric models at an e^+e^- linear collider with polarized beams. The production of light neutralinos e^+ e^- --> \tilde\chi^0_1 \tilde\chi^0_2 and the…
A search for pair production of supersymmetric particles in events with two oppositely charged leptons (electrons or muons) and missing transverse momentum is reported. The data sample corresponds to an integrated luminosity of 35.9…
A search was performed for charginos with masses close to the mass of the lightest neutralino in e+e- collisions at centre-of-mass energies of 189-209 GeV recorded by the OPAL detector at LEP. Events were selected if they had an observed…
A search for charginos and neutralinos, predicted by supersymmetric theories, has been performed using a data sample of 57 pb-1 at centre-of-mass energies of 181-184 GeV taken with the OPAL detector at LEP. No evidence for chargino or…
We have searched in $p \bar{p}$ collisions at $\sqrt{s}$ = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino…
Associated selectron-neutralino production in the process $e^-\gamma\to\tilde e^-\tilde\chi^0$ provides a striking supersymmetric signal: events with a single high $p_\perp$ electron and otherwise only invisible particles. For $e^-\gamma$…
In the minimal supersymmetric standard model, tau sleptons $\tilde \tau_{1,2}$ and neutralinos $\tilde \chi^0_{1,2}$ are expected to be among the lightest supersymmetric particles that can be produced copiously at future $e^+e^-$ linear…
We consider the process $e^+e^-\to\ti\chi^+_i\ti\chi^-_j$ at a linear collider with transverse $e^{\pm}$ beam polarization. We investigate the influence of the CP phases on azimuthal asymmetries in $e^+e^-\to\ti\chi^+_i\ti\chi^-_j$ with…
For the search for electroweak (EW) particles in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses of these particles an accurate knowledge of their production and decay properties is mandatory. We…
Searches for supersymmetric electroweakinos have entered a crucial phase, as the integrated luminosity of the Large Hadron Collider is now high enough to compensate for their weak production cross-sections. Working in a framework where the…
We study the potential of the LEP200 collider for chargino production and the possibility of the determination of some fundamental SUSY parameters through the relation with this study. Total cross sections for two basic signatures of pair…
Production and decay of gaugino-like charginos are crucially determined by sneutrino exchange. Therefore we study the pair production of charginos e^+ e^- -> chi^+_1 chi^-_1 with polarized beams and the subsequent decay chi^-_1 -> chi^0_1…
A search for charginos and neutralinos, predicted by supersymmetric theories, is performed using a data sample of 182.1 pb-1 taken at a centre-of-mass energy of 189 GeV with the OPAL detector at LEP. No evidence for chargino or neutralino…
In split supersymmetry, gauginos and Higgsinos are the only supersymmetric particles which are possibly accessible at foreseeable colliders. While the direct experimental searches, such as LEP and Tevatron experiments, gave robust lower…
The production of invisible pairs of lightest neutralinos accompanied by a large-angle hard photon in the reaction $e^+ e^- \to \chi^0_1 \chi^0_1 \gamma$ is studied at LEP2 energies. The most general gaugino/higgsino composition of the…
In supersymmetric grand unified theories, light higgsino multiplets generally exist in addition to the familiar chargino/neutralino multiplets of the minimal supersymmetric extension of the Standard Model. The new multiplets may include…
A search for charginos and neutralinos, predicted by supersymmetric theories, has been performed using a data sample of 10.3 pb^-1 at centre-of-mass energies of sqrt(s) = 170 and 172 GeV with the OPAL detector at LEP. No evidence for these…
We study the production processes e^+ e^- -> chi^+_i chi^-_j, i,j=1,2, and e^+ e^- -> chi^0_m chi^0_n, m,n=1,...,4, working out the advantages of polarizing both beams. For e^+ e^- -> chi^+_1 chi^-_1 with chi^-_1 -> chi^0_1 e^- nu and e^+…
The supersymmetric decays of the top quark into charged Higgs plus bottom, $\thb$, and into the supersymmetric partner of the top (${\wti u}_1$) plus the lightest neutralino (${\wti \chi}_1^0$), $\tstopneu$, are discussed within the…