High-Precision Comparisons of the Fundamental Properties of Antiprotons and Protons in BASE at CERN

According to the Standard Model of particle physics, the Big Bang has produced equal amounts of matter and antimatter. Cosmological observations however imply that the visible part of the universe is entirely made out of matter. This striking inconsistency inspires experiments to compare the fundamental properties of matter-antimatter conjugates at low energy and with high precision. The BASE collaboration at the antiproton decelerator of CERN is performing such high-precision comparisons with protons and antiprotons. Using advanced, ultra-stable, cryogenic Penning traps, we have performed the most precise measurement of the proton-to-antiproton charge-to-mass ratio with a fractional precision of 11 significant digits [1]. In another measurement, we have invented a novel spectroscopy method, which allowed for the first ultra-high precision measurement of the antiproton magnetic moment with a fractional precision of 1.5 parts in a billion [2]. Together with our recent measurement of the proton magnetic moment [3] this improves the precision of previous experiments [4] by more than a factor of 3000. In my talk I will review the recent achievements of BASE and will outline strategies to further improve our high-precision studies of matter-antimatter symmetry. Within my master thesis studies, I have contributed to the development of advanced spectroscopy and particle cooling methods, such as the implementation of a cooling trap technique for improved sub-thermal cooling cycles. This trap features a special trap design and a highly efficient cyclotron detector. We expect that the successful implementation of the method will considerably reduce experiment cycle times and thus enable magnetic moment measurements of the antiproton at 10-fold improved precision. [1] S. Ulmer et al., Nature 524, 196 (2015). [2] C. Smorra et al., Eur. Phys. Journ. Spec. Top. 224, 16 (2015). [3] G. Schneider et al., Science 358, 1081 (2017). [4] J. DiSciacca et al., Phys. Rev. Lett. 110, 130801 (2013).