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 propose several T-odd asymmetries in the decay chains of the top squarks $\tilde t_m \to t \tilde \chi^0_k$ and $t\to bW^+\to bl\nu$ and $\tilde\chi^0_k \to l^\pm\tilde l_n^\mp \to l^\pm l^\mp\tilde\chi^0_1$, for $l =e,\mu,\tau$. We calculate the asymmetries within the Minimal Supersymmetric Standard Model with complex parameters $M_1$, $\mu$ and $A_t$. We give the analytic formulae for the decay distributions. We present numerical results for the asymmetries and estimate the event rates necessary to observe them. The largest T-odd asymmetry can be as large as 40%.Comment: 26 pages, 5 figures; misprints corrected; reference adde

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 define a CP sensitive asymmetry in the sfermion decaysf → fχ 0 j ℓl , fχ 0 j qq, based on triple product correlations between the momenta of the outgoing fermions. We study this asymmetry in the MSSM with complex parameters. We show that the asymmetry is sensitive to the phases of the parameters µ and M 1 . The leading contribution stems from the decay chainf → fχ 0 j → fχ 0 1 Z → fχ 0 1 ℓl (fχ 0 1 qq), for which we obtain analytic formulae for the amplitude squared. The asymmetry can go up to 3% forf → fχ 0 1 ℓl, and up to 20% forf → fχ 0 1 qq. We also estimate the rates necessary to measure the asymmetry.

We study lepton flavour violating decays of neutralinos and sleptons within the Minimal Supersymmetric Standard Model, assuming two and three generation mixings in the slepton sector. We take into account the most recent bounds on flavour violating rare lepton decays. Taking the SPS1a' scenario as an example, we show that some of the lepton flavour violating branching ratios of neutralinos and sleptons can be sizable (∼ 5-10%). We study the impact of the lepton flavour violating neutralino and slepton decays on the di-lepton mass distributions measured at LHC. We find that they can result in novel and characteristic edge structures in the distributions. In particular, double-edge structures can appear in the eτ and µτ mass spectra ifτ 1 is the lightest slepton. The appearance of these remarkable structures provides a powerful test of supersymmetric lepton flavour violation at LHC.

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 %.

We present a phenomenological study of τ -sleptonsτ1,2 and τ -sneutrinosντ in the Minimal Supersymmetric Standard Model with complex parameters Aτ , µ and M1. We analyse production and decays of theτ1,2 andντ at a future e + e − collider. We present numerical predictions for the important decay rates, paying particular attention to their dependence on the complex parameters. The branching ratios of the fermionic decays ofτ1 andντ show a significant phase dependence for tan β < ∼ 10. For tan β > ∼ 10 the branching ratios for theτ2 decays into Higgs bosons depend very sensitively on the phases. We show how information on the phase ϕA τ and the other fundamentalτi parameters can be obtained from measurements of theτi masses, polarized cross sections and bosonic and fermionic decay branching ratios, for small and large tan β values. We estimate the expected errors of these parameters. Given favorable conditions, the error of Aτ is about 10% to 20%, while the errors of the remaining stau parameters are in the range of approximately 1% to 3%. We also show that the induced electric dipole moment of the τ -lepton is well below the current experimental limit.