High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e + e − linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.

The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.2

We study the decays of top squarks (stop_{1,2}) and bottom squarks (sbottom_{1,2}) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A_t, A_b, mu and M_1. We show that including the corresponding phases substantially affects the branching ratios of stop_{1,2} and sbottom_{1,2} decays in a large domain of the MSSM parameter space. We find that the branching ratios can easily change by a factor of 2 and more when varying the phases. This could have an important impact on the search for stop_{1,2} and sbottom_{1,2} and the determination of the MSSM parameters at future colliders.Comment: 17 pages, 5 figures, LaTeX2

We present a phenomenological study of top squarks (t 1,2 ) and bottom squarks (b 1,2 ) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A t , A b , µ and M 1 . In particular we focus on the CP phase dependence of the branching ratios oft 1,2 andb 1,2 decays. We give the formulae of the two-body decay widths and present numerical results. We find that the effect of the phases on thet 1,2 andb 1,2 decays can be quite significant in a large region of the MSSM parameter space. This could have important implications fort 1,2 andb 1,2 searches and the MSSM parameter determination in future collider experiments. We have also estimated the accuracy expected in the determination of the parameters oft i andb i by a global fit of the measured masses, decay branching ratios and production cross sections at e + e − linear colliders with polarized beams. Analysing two scenarios, we find that the fundamental parameters apart from A t and A b can be determined with errors of 1 % to 2 %, assuming an integrated luminosity of 1 ab −1 and a sufficiently large c.m.s. energy to produce also the heaviert 2 andb 2 states. The parameter A t can be determined with an error of 2 -3 %, whereas the error on A b is likely to be of the order of 50 %.

Abstract. We investigate the associated production of charged Higgs bosons (H ± ) and W bosons at the CERN Large Hadron Collider, using the leptonic decay H + → τ + ντ and hadronic W decay, within different scenarios of the Minimal Supersymmetric Standard Model (MSSM) with both real and complex parameters. Performing a parton level study we show how the irreducible Standard Model background from W + 2 jets can be controlled by applying appropriate cuts. In the standard m max h scenario we find a viable signal for large tan β and intermediate H ± masses (∼ mt). In MSSM scenarios with large mass-splittings among the heavy Higgs bosons the cross-section can be resonantly enhanced by factors up to one hundred, with a strong dependence on the CP-violating phases.