Impact of CP phases on stop and sbottom searches

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

Selectron production at an e-e- linear collider with transversely polarized beams

We study selectron production at an e-e- linear collider. With the help of transverse beam polarizations, we define CP sensitive observables in the production process e- e- --> selectron_L selectron_R. This process proceeds via t-channel and u-channel exchange of neutralinos, and is sensitive to CP violation in the neutralino sector. We present numerical results and estimate the significances to which the CP sensitive observables can be measured.Comment: 14 page

Impact of bosonic decays on the search for stau_2 and tau-sneutrino

We perform a detailed study of the decays of the heavier tau slepton (stau_2) and tau-sneutrino (snu_tau) in the Minimal Supersymmetric Standard Model (MSSM). We show that the decays into Higgs or gauge bosons, i.e. stau_2 -> stau_1 + (h^0, H^0, A^0 or Z^0), stau_2 -> snu_tau + (H^- or W^-), and snu_tau -> stau_1 + (H^+ or W^+), can be very important due to the sizable tau Yukawa coupling and large mixing parameters of stau. Compared to the decays into fermions, such as stau_2 -> tau + neutralino_i and stau_2 -> nu_tau + chargino_j^-, these bosonic decay modes can have significantly different decay distributions. This could have an important influence on the search for stau_2 and snu_tau and the determination of the MSSM parameters at future colliders.Comment: 12 pages, 3 figures, LaTeX2

CP sensitive observables in chargino production with transverse e±e^{\pm} beam polarization

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 subsequent two-body decays \ti\chi^-_j\to \ti\nu_{\ell}\ell^- and \ti\chi^-_j\to W^-\ti\chi^0_1. We show that triple product correlations involving the transverse $e^{\pm}$ beam polarization vanish if at least one subsequent chargino decay is not observed. We derive this result within the Minimal Supersymmetric Standard Model (MSSM) with complex parameters, however, it holds also in the general MSSM with SUSY flavour violation.Comment: 19 pages, 6 figure