WELCOME

Submitted by sulmer on Mon, 12/21/2020 - 12:00

BASE is a multinational collaboration at the Antiproton Decelerator (AD) of CERN which aims at precise comparisons of the fundamental properties of antiprotons and protons. Such comparisons provide stringent tests of charge-parity-time reversal invariance which is the most fundamental symmetry in the Standard Model of particle physics.

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.

First explicit measurement of heating rates in a cryogenic Penning trap

Submitted by sulmer on Mon, 01/28/2019 - 17:20

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.

11-fold improved measurement of the proton magnetic moment

Submitted by sulmer on Thu, 11/23/2017 - 22:34

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.