Gudrid Moortgat-Pick

SUSY parameter determination in combined analyses at LHC / LC

We demonstrate how the interplay of a future e+e− LC at its first stage with (s)1/2500 GeV and of the LHC could lead to a precise determination of the fundamental SUSY parameters in the gaugino/higgsino sector without assuming a specific supersymmetry breaking scheme. We demonstrate this for the benchmark scenario SPS1a, taking into account realistic errors for the masses and cross sections measured at the LC with polarised beams, including errors coming from polarisation measurements, and mass measurements at the LHC. The results clearly demonstrate the complementarity of the LHC and LC, and the benefit from the joint analyses of their data.

A T-odd asymmetry in neutralino production and decay

We study CP-violating effects in neutralino production and subsequent decay within the Minimal Supersymmetric Standard Model with complex parameters M1 and ?. The observable we propose is a T-odd asymmetry based on a triple product in neutralino production e+e??0i02, i = 1,...,4?, with subsequent leptonic three-body decay 02?01?+??, ? = e,?, at an e+e? linear collider with (s)1/2 = 500?GeV and polarised beams. We provide compact analytical formulae for the cross section and the T-odd asymmetry taking into account the complete spin correlations between production and decay. We give numerical predictions for the cross section and the T-odd asymmetry. The asymmetry can go up to 10 %.

Measurement of CP violation in stop cascade decays at the LHC

AbstractWe study the potential observation at the LHC of CP-violating effects in stop production and subsequent cascade decays,

Theoretical upper bound on the mass of the LSP in the MNSSM

gg\to \tilde{t}_{i}\tilde{t}_{i}

Towards measuring the stop mixing angle at the LHC

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Probing CP violation with and without momentum reconstruction at the LHC

\tilde{t}_{i}\to t\tilde{\chi}^{0}_{j}

Discriminating Z ′ from anomalous trilinear gauge coupling signatures in e + e − → W + W − at ILC with polarized beams

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Development of a Superconducting Helical Undulator for a Polarised Positron Source

\tilde{\chi}^{0}_{j}\to \tilde{\chi}^{0}_{1}\ell^{+}\ell^{-}

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

, within the Minimal Supersymmetric Standard Model. We study T-odd asymmetries based on triple products between the different decay products. There may be a large CP asymmetry at the parton level, but there is a significant dilution at the hadronic level after integrating over the parton distribution functions. Consequently, even for scenarios where large CP intrinsic asymmetries are expected, the measurable asymmetry is rather small. High luminosity and precise measurements of masses, branching ratios and CP asymmetries may enable measurements of the CP-violating parameters in cascade decays at the LHC.

Development of a full scale superconducting undulator module for the ILC positron source

We study the neutralino sector of the Minimal Non-minimal Supersymmetric Standard Model (MNSSM) where the μ problem of the Minimal Supersymmetric Standard Model (MSSM) is solved without accompanying problems related with the appearance of domain walls. In the MNSSM as in the MSSM the lightest neutralino can be the absolutely stable lightest supersymmetric particle (LSP) providing a good candidate for the cold dark matter component of the Universe. In contrast with the MSSM the allowed range of the mass of the lightest neutralino in the MNSSM is limited. We establish the theoretical upper bound on the lightest neutralino mass in the framework of this model and obtain an approximate solution for this mass.