A widely tunable few electron droplet

Quasi-static transport measurements are employed to characterize a few electron quantum dot electrostatically defined in a GaAs/AlGaAs heterostructure. The gate geometry allows observations on one and the same electron droplet within a wide range of coupling strengths to the leads. The weak coupling regime is described by discrete quantum states. At strong interaction with the leads Kondo phenomena are observed as a function of a magnetic field. By varying gate voltages the electron droplet can, in addition, be distorted into a double quantum dot with a strong interdot tunnel coupling while keeping track of the number of trapped electrons.Comment: 11 pages, 5 figure

Production of Stop, Sbottom, and Stau at LEP2

We present a comprehensive study of pair production and decay of stops, sbottoms, and staus in $e^+ e^-$ annihilation at LEP2. We give numerical predictions within the Minimal Supersymmetric Standard Model for cross sections and decay rates, and discuss the important signatures. In the case of stau production we also study the polarization of the tau in the decays stau_1 -> tau + neutralino_{1,2}.Comment: 15 pages, LateX, 13 figures appended as uuencoded PS-file. LateX file and figures are also available via anonymous ftp at ftp://info.oeaw.ac.at/pub/hephy-pub/64

Scalar Top Quark Production at μ+μ−\mu^+ \mu^- Colliders

We discuss the production of stops at a $\mu^+ \mu^-$ collider. We present numerical predictions for the cross sections within the Minimal Supersymmetric Standard Model. In particular we consider stop production near $\sqrt{s} = m_{H^0}$ and $\sqrt{s} = m_{A^0}$.Comment: 6 pages LaTeX including 5 figures. Talk presented by W. Porod at the "Workshop on Physics at the First Muon Collider and the Front End of a Muon Collider", November 6 - 9, 1997, FNAL, Batavia, Illinois, US

Phenomenology of stops, sbottoms, tau-sneutrinos, and staus at an e+e- Linear Collider

We discuss production and decays of stops, sbottoms, tau-sneutrinos, and staus in e+e- annihilation in the energy range \sqrt{s} = 0.5-1 TeV. We present numerical predictions within the Minimal Supersymmetric Standard Model for cross sections and decay rates, including one-loop radiative corrections as well as initial state radiation. We also study the importance of beam polarization for the determination of the underlying SUSY parameters. Moreover, we make a comparison of the potential to study squarks and sleptons of the 3rd generation between Tevatron, LHC, and Linear Collider.Comment: Version to be published in EPJdirec