Laser spectroscopy on fast 7Li+ ions for a test of Lorentz invariance
Dipl.-Phys. Benjamin Botermann (Institut für Kernchemie & GSI Helmholtzzentrum für Schwerionenforschung GmbH)

One of the fundamental principles in modern physics is Local Lorentz Invariance (LLI), on which the theory of Special Relativity (SR) is based. Special Relativity can be probed by a careful measurement of time dilation. For this, an accelerated ion-beam of 7Li+ ions at a velocity (v) of 33,8 % of the speed of light (c) is illuminated by two laser beams to excite the moving ions. The lithium ions are produced by an PIG ion source, accelerated in the SIS18-synchrotron and stored in the experimental storage ring at the GSI Helmholtzzentrum für Schwerionenforschung.

The precission of 10-9 is provided by a laser stabilization scheme using saturation spectroscopy on rubidium and iodine.
Considering all other experimental uncertainties, this leads to an upper bound for hypothetical deviations from SR of the order of 10??8. In our recent measurements the results of the so far leading experiment [3] has been improved by roughly a factor of 4.
[1] R. Mansouri, and R. U. Sexl, General Relativity an Gravitation 8, 497 - 513 (1977)
[2] D. Colladay, and V. A. Kostelecky, Physical Review D 58, 116002 (1998)
[3] S. Reinhardt et al., Nature Physics 3, 861 - 864 (2007)

Further details on the pdf at the webpage.