We developed a technique to extract arbitrary fractions of antiprotons in a reservoir trap. This method enables us to operate BASE almost independent from accelerator cycles, and especially during the winter shut-down when magnetic field noise in the antiproton decelerator hall is low. For further details read this article.  

In a paper published today in Nature we report the high-precision comparison of the antiproton-to-proton charge to mass ratio. In our measurements we compared the cyclotron frequencies of antiprotons to that of negatively charged hydrogen ions, which are used as a proxy for the proton. We achieved a fractional precision of 69 parts in a trillion, which corresponds in our magnetic field of 1.95 Tesla to an absolute energy resolution of 2mHz. Our result is consistent with CPT invariance.

BASE member Stefan Ulmer has been selected to receive the IUPAP Young Scientist Prize 2014 in Fundamental Metrology. With this prize the International Union of Pure and Applied Physics (IUPAP) honors his work on proton and antiproton magnetic moment measurements.

In a paper just published in Nature we report on the first direct high precision measurement of the proton magnetic moment. By application of the elegant double Penning trap technique we achieved a fractional precision of 3.3 parts per billion. Our value is consistent with the currently accepted CODATA value, but 2.5 times more precise.

Congratulations, BASE member Dr. Christian Smorra applied successfully for one of the highly competitive CERN fellowships. We are thankful for the very strong support by CERN.

In a just in Physics Letters B published article we report on the first successful demonstration of the double Penning trap technique with a single proton. This is a major step towards a  measurement of the particle's magnetic moment with ppb precision. The method can be applied to the antiproton, which will enable one of the most sensitive tests of CPT symmetry with baryons.

In today's Research Board meeting the BASE project was approved. CERN supported the approval by an article in the CERN bulletin.

The BASE technical design report was evaluated by the SPSC. The committee recommended approval of the BASE project to the research board. Our TDR contains a detailed description of our experiment and a feasibility study for implementation of BASE into the Antiproton Decelerator facility. We acknowledge the strong support of the CERN groups which contributed to to this study.Special thanks to Lajos Bojtar for the coordination.

In a just in Physical Review Letters published article we report on the first detection of single spin-flips of a single proton. We use Bayesian analysis methods and obtain spin state detection fidelities close to 100%. This is a major step towards the application of the so-called double Penning-trap method to measure magnetic moments of both the proton and the antiproton with ppb precision.

The BASE Letter of Intent was welcomed by the CERN SPSC. We are invited to submit a technical design report, discussing the feasibility to implement our apparatus into the infrastructure of the Antiproton Decelerator facility.