Today we report in SCIENCE on a new measurement of the proton magnetic moment in units of the nuclear magneton. The updated value gp/2=2.792 847 344 62 (82) is consistent with our previous best measurement, but improves the precision by a factor of 11. The measurement was carried out using an optimized double Penning trap technique. Compared to our 2014 measurement, a trap with higher magnetic field stability and homogeneity was implemented.
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.
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.
Today our article on an improved measurement of the magnetic moment of the antiproton, with a fractional precision of 0.8 parts in a million, was published in Nature Communications. This is, so far, the culmination point of 10 years of dedicated work on proton and antiproton magnetic moment measurements.
Our colleagues from the ALPHA collaboration just published an article on the Observation of the 1S/2S Transition in Trapped Antihydrogen.
We congratulate to this fantastic result!!!
The construction of ELENA, the Extra Low Energy Antiproton Ring, which is dedicated to slow-down the 5.3 MeV AD antiprotons to keV energies has been finished and is entering the commissioning phase. In a recent AD users meeting the ELENA team around project coordinator Christian Carli has reported on first circulating beam, CONGRATULATIONS! For more information read the CERN courier article.
Our article "Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons" has been published in Review of Scientific Instruments. There we describe highly sensitive image-current detection systems based on superconducting toroidal coils and ultra-low noise amplifiers for non-destructive measurements of the axial frequencies (550–800 kHz) of single antiprotons stored in the BASE multi-Penning-trap system.