A 16 parts-per-trillion comparison of the proton/antiproton charge-to-mass ratios

Submitted by sulmer on Fri, 07/15/2022 - 17:49

In a paper published today in Nature, we report on the most precise comparison between a fundamental property of protons and antiprotons. Analysing a total of about 24000 proton and antiproton cyclotron frequency measurements, taken over the course of one year and half, we found that the charge-to-mass ratios of protons and antiprotons are identical to within a record experimental uncertainty of 16 parts per trillion, see Fig. 1.


Submitted by sulmer on Fri, 07/15/2022 - 17:47

Today, we report in Nature on the first sympathetic cooling of a single trapped proton, using laser-cooled beryllium ions stored in a spatially separated trap. The energy exchange between the proton and the laser-cooled ions is mediated by image currents induced by the ions in the trap electrodes, transmitted through a superconducting LC circuit that connects the traps (see Figure 1).

BASE and ALPHA in the Top 10 of Physics Breakthroughs 2021

Submitted by sulmer on Fri, 07/15/2022 - 17:46

One of the highlights in the annual Physics calendar is the announcement of the “Physics Breakthroughs of the Year”, by the journal Physics World. This year, our paper on "Sympathetic cooling of protons mediated by a superconducting LC-circuit", published in Nature, was selected as one of the top ten achievements made in 2021.

Detection of metastable electronic states by Penning trap mass spectrometry

Submitted by sulmer on Wed, 05/06/2020 - 21:22

We congratulate our friends at PENTATRAP at the Max Planck Institute for Nuclear Physics in Heidelberg, which report here on the detection of a 200eV excited metastable state in highly charged Rhenium, identified by a 10 ppt mass measurement. Also some BASE members were involved in the study.

Superconducting Solenoid System with Adjustable Shielding Factor for Precision Measurements of the Properties of the Antiproton

Submitted by sulmer on Sat, 10/05/2019 - 00:01

Today we published a new paper in Physical Review Applied, on an innovative, tunable magnetic shielding system. With the tuned system, we suppress external magnetic field disturbances by up to a factor of 225 ± 15. Together with other developments, this will enable future antiproton-to-proton charge-to-mass ratio comparisons with fourfold reduced frequency fluctuations and antiproton magnetic moment determinations with about tenfold reduced uncertainty.

IUPAP Prize for Atomic, Molecular, and Optical Physics 2019 awarded to BASE members Christian Smorra and Andreas Mooser

Submitted by sulmer on Tue, 07/16/2019 - 15:43

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.

Center for Time, Constants, and Fundamental Symmetries

Submitted by sulmer on Wed, 04/10/2019 - 08:38

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.

CERN research fellowships awarded to BASE members

Submitted by sulmer on Tue, 02/12/2019 - 11:20

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.