https://doi.org/10.1140/epjst/e2015-02607-4
Review
BASE – The Baryon Antibaryon Symmetry Experiment
1 Ulmer Initiative Research Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
2 CERN, 1211 Geneva 23, Switzerland
3 Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
4 Institute of Quantum Optics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
5 Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
6 Helmholtz-Institut Mainz, 55099 Mainz, Germany
7 Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
8 Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
9 GSI-Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
10 Ruprecht-Karls-Universität Heidelberg, 69047 Heidelberg, Germany
11 Atomic Physics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
a e-mail: Christian.Smorra@cern.ch
Received: 21 September 2015
Revised: 1 October 2015
Published online: 23 November 2015
The Baryon Antibaryon Symmetry Experiment (BASE) aims at performing a stringent test of the combined charge parity and time reversal (CPT) symmetry by comparing the magnetic moments of the proton and the antiproton with high precision. Using single particles in a Penning trap, the proton/antiproton g-factors, i.e. the magnetic moment in units of the nuclear magneton, are determined by measuring the respective ratio of the spin-precession frequency to the cyclotron frequency. The spin precession frequency is measured by non-destructive detection of spin quantum transitions using the continuous Stern-Gerlach effect, and the cyclotron frequency is determined from the particle*s motional eigenfrequencies in the Penning trap using the invariance theorem. By application of the double Penning-trap method we expect that in our measurements a fractional precision of δg/g 10−9 can be achieved. The successful application of this method to the antiproton will consist a factor 1000 improvement in the fractional precision of its magnetic moment. The BASE collaboration has constructed and commissioned a new experiment at the Antiproton Decelerator (AD) of CERN. This article describes and summarizes the physical and technical aspects of this new experiment.
© EDP Sciences, Springer-Verlag, 2015