Experimental benchmarking of spin tracking algorithms for electric dipole moment searches at the cooler synchrotron COSY

Known CP violating sources in the Standard Model of Particle Physics are not sufficient to explain the predominance of the observed matter in the Universe. Additional sources beyond the Standard Model are required. These sources can manifest in permanent electric dipole moments (EDMs) of elementary particles. Searches for neutral particles already started decades ago, but no value significantly different from zero has been observed. The current upper limit for the neutron amounts to 2.9 · 10^−26 e cm (90% C. L.). New measurement methods for protons and deuterons in dedicated electrostatic storage rings are proposed. As an intermediate step, essential requirements and limitations are studied by the JEDI (Jülich Electric Dipole moments Investigations) collaboration at the existing magnetic storage ring, the Cooler Synchrotron COSY. A first direct measurement of the deuteron EDM is planned, which employs a radiofrequency (RF) Wien filter to create an EDM related spin polarization signal. In the scope of this thesis a new framework providing a convenient environment for simulation and analysis was created to model this new method. It interfaces with the existing simulation code COSY INFINITY to calculate transfer maps for the particle beam and spin coordinates. These maps are used to perform repetitive tracking. New transfer map based algorithms have been implemented to extend the functionality for time-varying electromagnetic fields. One of the major requirements for storage ring based EDM searches is a long spin coherence time, which limits the available time to conduct the measurement. Important contributions to spin decoherence arising from path-lengthening of individual particles and from intrinsic spin resonances have been discussed and verified by simulation studies. To cancel those contributions, storage ring parameters like betatron tunes, chromaticities and momentum compaction factors require precise adjustment. The measured locations of longest spin coherence times confirmed the model predictions for different betatron tunes. Based on a conservative definition, spin coherence times of about 750 s have been achieved during these studies at COSY. The long spin coherence time allowed for the benchmarking of the new algorithms for time-varying fields. An existing RF solenoid running on an artificial spin resonance was used to introduce vertical polarization oscillations. Theoretical calculations predict a dependence of the oscillation amplitude on the solenoid frequency. These calculations were successfully verified by simulations and measurements. Also analytical estimates of the EDM related polarization could be confirmed by the new algorithms. Systematic contributions mimicking this signal arise from misalignments and field imperfections of the RF Wien filter or the storage ring magnets. Calculations predicted that an RF Wien filter rotation about the longitudinal axis by 0.1 mrad produces a similar signal as an EDM 5 · 10^−19 e cm. The same order of magnitude was obtained by randomly shifting the quadrupole magnets in vertical direction assuming a Gaussian distribution with a width of 0.1 mm. Finally, orbit correction methods to suppress these systematic contributions were applied in simulations. These partially compensated the false EDM signal contributions from misalignments of the static storage ring elements