A. Bartl

The role of polarized positrons and electrons in revealing fundamental interactions at the Linear Collider

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.

Production and decay of neutralinos in e+e− annihilation

Abstract We study in detail production and decay of neutralinos in e + e − annihilation. Formulae for the cross section, the single lepton, lepton pair, and missing energy spectra are given. Particular attention is paid to the mixing of gauginos and higgsinos. In order to illustrate its importance numerical results for four different mixing scenarios are presented.

Effect of supersymmetric phases on lepton dipole moments and rare lepton decays

We study the effect of SUSY phases on rare decays of leptons and on their magnetic and electric dipole moments. We consider the most general mass matrices for sleptons within the MSSM including left–right mixing, flavour mixing and complex phases. We show that the phases also affect CP even observables. Moreover, we demonstrate that contrary to common belief the phase of µ can be large even for slepton masses as small as 200 GeV provided the lepton flavour violating parameters are complex.

LHC phenomenology of the mu nu SSM

35 pages, 23 figures.-- ISI article identifier: 000267789100120 .-- ArXiv pre-print avaible at: http://arxiv.org/abs/0903.3596

CP asymmetries in neutralino production in e + e − -collisions

We study two CP sensitive triple-product asymmetries for neutralino production e + e − → ˜ χ 0 ˜ χ 0 and the subsequent leptonic two-body decay ˜ χ 0 → ˜ l l, ˜ → ˜ χ 0 l, for l = e, �, τ . We calculate the asymmetries, cross sections and branching ratios in the ˜

SUSY-QCD corrections to scalar quark decays into charginos and neutralinos

We calculate the supersymmetric O(αs) QCD corrections to the decays qi → q′ χj± (i, j = 1, 2) and qi → qχk0 (k = 1,…, 4) within the Minimal Supersymmetric Standard Model. In particular we consider the decays of squarks of the third generation, ti and bi (i = 1, 2), where the left-right mixing must be taken into account. The corrections turn out to be of about 10%, except for higgsino-like charginos or neutralinos, where they can go up to 40%.

Squark and gluino decays for large tan β

AbstractWe have studied stop, sbottom and gluino decays in a scenario with large tan β, where both

A T-odd asymmetry in neutralino production and decay

\tilde t_L - \tilde t_R