The IUPAP Prize for Atomic, Molecular, and Optical Physics 2019 was awarded to the BASE members Christian Smorra (RIKEN and CERN) and Andreas Mooser (RIKEN and MPIK). The highly competitive research prize was awarded…

“…for outstanding contributions to determine the most precise comparison of the proton-to-antiproton charge-to-mass ratios and the most precise comparison of the proton and antiproton magnetic moments, constituting two different world-record tests of the fundamental charge, parity, and time reversal symmetry in these systems.”

Today we’ve celebrated the inauguration of the Max-Planck/PTB/RIKEN Center for Time, Constants and Fundamental Symmetries, the event took place at RIKEN’s Wako-Campus in Japan. We’ve organized a symposium with invited speakers Marianna Safronova (Univ. Delaware) and Yoshiro Takahashi (Kyoto University), and center speakers Klaus Blaum (MPG), Ekkehard Peik (PTB), and Stefan Ulmer (RIKEN). Guests like Prof. M. Stratmann (President MPG), Prof. J. Ullrich (President PTB), Prof. S. Koyasu and Prof. M. Kotani (RIKEN Executive Directors), and Dr. H. von Werthern, the ambassador of Germany in Japan, joined the event.

We are happy to announce that the future research of our team members Elise Wursten and Jack Devlin will be supported by two individual, highly competitive CERN research fellowships. We greatfully acknowledge the invaluable support by CERN. Elise Wursten joined the BASE team in July 2018, she was previously working on measurements of the electric dipole moment of the neutron.

Today we report on the first explicit measurement of cyclotron quantum heating rates in a cryogenic Penning trap. We demonstrate that the scaled electric field noise in our spin-analysis trap, an essential instrument in our 1.5 p.p.b. measurement of the antiproton magnetic moment, is much lower than observed in other ion trap experiments. It corresponds to a heating rate below 0.1 quanta per hour and a radial energy stability on the peV/s-level.

In the entire 2016 antiproton run BASE was operated with particles trapped in 2015. The particles were suspended from the unique reservoir trap to the measurement traps on request, apart from dispensing single antiprotons to the other traps, not a single antiproton was lost in an integrated observation time of in total 405 days.

Today a paper was published in Phys. Rev. Lett.in which a collaboration of researchers from Max Planck Institute for Nuclear Physics, Heidelberg, Germany and Members of BASE/RIKEN's Ulmer Fundamental Symmetries Lab report on a three-fold improved measurement of the proton mass in natural units.

The japanese research institute RIKEN will continue its strong support of the work of the BASE collaboration. To this end the new, dedicated "fundamental symmetries laboratory (FSL)" has been opened. The major research goal of FSL will be to push the limits in ultra-precise comparisons of the fundamental properties of protons and antiprotons.

Today we have published a paper in Phys. Lett. B, in which we report on the detection of individual spin quantum transitions of a single trapped antiproton in a Penning trap. The spin state determination is based on the unambiguous detection of axial frequency shifts which are induced by the spin transition in presence of a magnetic bottle. We have achieved a detection fidelity of 92.6 % and demonstrated spin state initialization with 99.9% fideltiy.