Determination of the Invariant Spin Axis in a COSY model using Bmad

The matter-antimatter asymmetry might be understood by investigating the EDM (ElectricDipole Moment) of elementary particles. A permanent EDM of a subatomic particle violatestime reversal and parity symmetry at the same time and would be, with the currently achievableexperimental accuracy, an indication for further CP violation than established in the SM(Standard Model of Particle Physics). The JEDI-Collaboration (J¨ulich Electric Dipole momentInvestigations) in J¨ulich has performed a direct EDM measurement for deuterons with the so-called precursor experiments at the storage ring COSY (COoler SYnchrotron) by measuringthe orientation of the ISA (Invariant Spin Axis). In order to interpret the measured data andto disentangle a potential EDM signal from systematic effects, spin tracking simulations in anaccurate simulation model of COSY are needed. Therefore a model of COSY was implementedusing the software library Bmad. Systematic effects were considered by including elementmisalignments, effective dipole shortening, longitudinal fields and steerer kicks. These effectsrotate the ISA in addition to the EDM and have to be analyzed and understood. The mostrecent spin tracking results as well as the methods to find the ISA are presented in this paper.