# High-precision comparison of the antiproton-to-proton charge-to-mass ratio

@article{Ulmer2015HighprecisionCO, title={High-precision comparison of the antiproton-to-proton charge-to-mass ratio}, author={Stefan Ulmer and Christian Smorra and Andreas H. Mooser and K. A. Franke and H. Nagahama and G. Schneider and Takashi Higuchi and Simon Van Gorp and Klaus Blaum and Yasuyuki Matsuda and Wolfgang Quint and Jochen Walz and Yasunori Yamazaki}, journal={Nature}, year={2015}, volume={524}, pages={196-199} }

Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry—that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime—although it is model dependent. A number of high…

## 111 Citations

Particle physics: Matter and antimatter scrutinized

- PhysicsNature
- 2015

Stefan Ulmer et al. test the CPT theorem by measuring whether particles and antiparticles, apart from a sign change, are identical, and compare the antiproton charge-to-mass ratio to its proton counterpart, showing that the C PT theorem holds at the atto-electronvolt scale.

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

- PhysicsPhilosophical 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

- PhysicsNature
- 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.

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

- PhysicsNature 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.

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

- PhysicsNature
- 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.

Precision measurement of the mass difference between light nuclei and anti-matter counterparts

- Physics
- 2015

In ultra relativistic heavy-ion collisions a large and similar amount of nuclei and anti-nuclei is produced in the central pseudorapidity region allowing one to thoroughly investigate their…

BASE – The Baryon Antibaryon Symmetry Experiment

- Physics
- 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…

Lorentz and
CPT
tests with charge-to-mass ratio comparisons in Penning traps

- Physics
- 2020

Applications of the general theory of quantum electrodynamics with Lorentz- and CPT-violating operators of mass dimensions up to six are presented to Penning-trap experiments comparing charge-to-mass…

Testing CPT And Antigravity With Trapped Antihydrogen At ALPHA

- Physics
- 2015

High precision antihydrogen experiments allow tests of fundamental theoretical descriptions of nature. These experiments are performed with the ALPHA apparatus, where ultra-low energy antihydrogen is…

Tests of the CPT Invariance at the Antiproton Decelerator of CERN

- PhysicsUkrainian Journal of Physics
- 2019

The Standard Model, the theory of particle physics is based on symmetries: both the structure of the composite particles and their interactions are derived using gauge invariance principles. Some of…

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