# BASE – The Baryon Antibaryon Symmetry Experiment

@article{Smorra2015BASET, title={BASE – The Baryon Antibaryon Symmetry Experiment}, author={Christian Smorra and Klaus Blaum and Lajos Bojt{\'a}r and M. Borchert and K. A. Franke and Takashi Higuchi and Nathan Leefer and H. Nagahama and Yasuyuki Matsuda and Andreas H. Mooser and Malte Niemann and Christian Ospelkaus and Wolfgang Quint and G. Schneider and Stefan Sellner and T. Tanaka and S. Van Gorp and Jochen Walz and Yasunori Yamazaki and Stefan Ulmer}, journal={The European Physical Journal Special Topics}, year={2015}, volume={224}, pages={3055-3108} }

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…

## 39 Citations

Sixfold improved single particle measurement of the magnetic moment of the antiproton

- Physics, MedicineNature communications
- 2017

This work reports on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level that agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics.

Challenging the standard model by high-precision comparisons of the fundamental properties of protons and antiprotons

- Physics, MedicinePhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
- 2018

The BASE collaboration investigates the fundamental properties of protons and antiprotons, such as charge-to-mass ratios and magnetic moments, using advanced cryogenic Penning trap systems, and sets the most stringent constraint on directly measured antiproton lifetime.

A parts-per-billion measurement of the antiproton magnetic moment

- Physics, MedicineNature
- 2017

A high-precision measurement of the magnetic moment of the antiproton in units of the nuclear magneton μN with a fractional precision of 1.5 parts per billion is reported, which constrains the magnitude of certain CPT-violating effects to below 1.8 × 10−24 gigaelectronvolts.

350-fold improved measurement of the antiproton magnetic moment using a multi-trap method

- PhysicsHyperfine Interactions
- 2018

We summarize our recent 1.5 parts per billion measurement of the antiproton magnetic moment using the multi Penning-trap system of the BASE collaboration. The result was achieved by combining the…

A 16-parts-per-trillion measurement of the antiproton-to-proton charge–mass ratio

- MedicineNature
- 2022

A new comparison of the proton/antiproton charge-to-mass ratios with a fractional uncertainty of 16 parts per trillion is reported, consistent with the fundamental charge–parity–time reversal invariance, and improves the precision of the previous best measurement by a factor of 4.3.

Double-trap measurement of the proton magnetic moment at 0.3 parts per billion precision

- Physics, MedicineScience
- 2017

A direct high-precision measurement of the magnetic moment μp of the proton in units of the nuclear magneton μN is reported, which improves the previous best measurement by a factor of 11, and is consistent with the currently accepted value.

Low-energy antimatter experiments at the antiproton decelerator at CERN: Testing CPT invariance and the WEP

- PhysicsJournal of Physics: Conference Series
- 2018

The riddle of the baryon asymmetry, i.e. the matter antimatter imbalance in the universe can be addressed by comparing matter particles with their antimatter counterparts. At the antiproton…

Towards sympathetic cooling of single (anti-)protons

- PhysicsHyperfine Interactions
- 2018

We present methods to manipulate and detect the motional state and the spin state of a single antiproton or proton which are currently under development within the BASE (Baryon Antibaryon Symmetry…

Quantum logic inspired techniques for spacetime-symmetry tests with (anti-)protons

- PhysicsNew Journal of Physics
- 2021

Cosmological observations as well as theoretical approaches to physics beyond the standard model provide strong motivations for experimental tests of fundamental symmetries, such as CPT invariance.…

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