Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Riddle of matter remains unsolved: Proton and antiproton share fundamental properties

19.10.2017

Magnetic forces in antiprotons now measured to nine significant digits—350 times more precise than before

The search goes on. No difference in protons and antiprotons have yet been found which would help to potentially explain the existence of matter in our universe. However, physicists in the BASE collaboration at the CERN research center have been able to measure the magnetic force of antiprotons with almost unbelievable precision. Nevertheless, the data do not provide any information about how matter formed in the early universe as particles and antiparticles would have had to completely destroy one another.


BASE Penning trap system to measure magnetic movement of the antiproton

photo/©: Stefan Sellner, Fundamental Symmetries Laboratory, RIKEN, Japan


BASE experiment at the CERN antiproton decelerator in Geneva: Visible in the image are the control equipment, the superconducting magnet that houses the Penning trap, and the antiproton transfer beam tube.

photo/©: Stefan Sellner, Fundamental Symmetries Laboratory, RIKEN, Japan

The most recent BASE measurements revealed instead a large overlap between protons and antiprotons, thus confirming the Standard Model of particle physics. Around the world, scientists are using a variety of methods to find some difference, regardless of how small. The matter-antimatter imbalance in the universe is one of the hot topics of modern physics.

The multinational BASE collaboration at the European research center CERN brings together scientists from the RIKEN research center in Japan, the Max Planck Institute for Nuclear Physics in Heidelberg, Johannes Gutenberg University Mainz (JGU), the University of Tokyo, GSI Darmstadt, Leibniz Universität Hannover, and the German National Metrology Institute (PTB) in Braunschweig.

They compare the magnetic properties of protons and antiprotons with great precision. The magnetic moment is an essential component of particles and can be depicted as roughly equivalent to that of a miniature bar magnet. The so-called g-factor measures the strength of the magnetic field. "At its core, the question is whether the antiproton has the same magnetism as a proton," explained Stefan Ulmer, spokesperson of the BASE group. "This is the riddle we need to solve."

The BASE collaboration published high-precision measurements of the antiproton g-factor back in January 2017 but the current ones are far more precise. The current high-precision measurement determined the g-factor down to nine significant digits. This is the equivalent of measuring the circumference of the earth to a precision of four centimeters. The value of 2.7928473441(42) is 350 times more precise than the results published in January.

"This tremenduous increase in such a short period of time was only possible thanks to completely new methods," said Ulmer. The process involved scientists using two antiprotons for the first time and analyzing them with two Penning traps.

Antiprotons stored a year before analysis

Antiprotons are artificially generated at CERN and researchers store them in a reservoir trap for experiments. The antiprotons for the current experiment were isolated in 2015 and measured between August and December 2016, which is a small sensation as this was the longest storage period for antimatter ever documented. Antiprotons are usually quickly annihilated when they come into contact with matter, such as in air. Storage was demonstrated for 405 days in a vacuum, which contains ten times fewer particles than interstellar space. A total of 16 antiprotons were used and some of them were cooled to approximately absolute zero or minus 273 degrees Celsius.

The new principle uses the interaction of two Penning traps. The traps use electrical and magnetic fields to capture the antiprotons. Previous measurements were severely limited by an ultra-strong magnetic inhomogeneity in the Penning trap. In order to overcome this barrier, the scientists added a second trap with a highly homogeneous magnetic field. "We thus used a method developed at Mainz University that created higher precision in the measurements," explained Ulmer. "The measurement of antiprotons was extremely difficult and we had been working on it for ten years. The final breakthrough came with the revolutionary idea of performing the measurement with two particles." The larmor frequency and the cyclotron frequency were measured; taken together they form the g-factor.

The g-factor ascertained for the antiproton was then compared to the g-factor for the proton, which BASE researchers had measured with the greatest prior precision already in 2014. In the end, however, they could not find any difference between the two. This consistency is a confirmation of the CPT symmetry, which states that the universe is composed of a fundamental symmetry between particles and antiparticles. "All of our observations find a complete symmetry between matter and antimatter, which is why the universe should not actually exist," explained Christian Smorra, first author of the study. "An asymmetry must exist here somewhere but we simply do not understand where the difference is. What is the source of the symmetry break?"

The BASE scientists now want to use even higher precision measurements of the proton and antiproton properties to find an answer to this question. The BASE collaboration plans to develop further innovative methods over the next few year and improve on the current results.

Images:
http://www.uni-mainz.de/bilder_presse/08_physik_quantum_BASE_antiprotonen-entsch...
BASE experiment at the CERN antiproton decelerator in Geneva: Visible in the image are the control equipment, the superconducting magnet that houses the Penning trap, and the antiproton transfer beam tube.
photo/©: Stefan Sellner, Fundamental Symmetries Laboratory, RIKEN, Japan

http://www.uni-mainz.de/bilder_presse/08_physik_quantum_BASE-penningfallensystem...
BASE Penning trap system to measure magnetic movement of the antiproton
photo/©: Stefan Sellner, Fundamental Symmetries Laboratory, RIKEN, Japan

Publication:
Christian Smorra et al.
A parts-per-billion measurement of the antiproton magnetic moment
Nature, 19 October 2017
DOI: 10.1038/nature24048

Contact and further information:
Dr. Stefan Ulmer
Chief Scientist, Ulmer Fundamental Symmetries Laboratory
RIKEN
2-1 Hriosawa, Wako, 351-0198 Saitama, JAPAN
Spokesperson BASE collaboration
CERN
1211 Genf, SWITZERLAND
phone: +41 75 411 9072
e-mail: stefan.ulmer@cern.ch
http://ulmerfsl.riken.jp/index.html

Professor Dr. Jochen Walz
Quantum, Atomic, and Neutron Physics (QUANTUM)
Institute of Physics
Johannes Gutenberg University Mainz
55099 Mainz, GERMANY
phone: +49 6131 39-25976
fax: +49 6131 39-25179
e-mail: Jochen.Walz@uni-mainz.de
http://www.quantum.physik.uni-mainz.de

Professor Dr. Klaus Blaum
Stored and Cooled Ions Division
Max Planck Institute for Nuclear Physics
Saupfercheckweg 1
69117 Heidelberg, GERMANY
phone: +49 6221 516-851
fax: +49 6221 516-852
e-mail: Klaus.Blaum@mpi-hd.mpg.de
https://www.mpi-hd.mpg.de/blaum/index.en.html

Professor Dr. Christian Ospelkaus
Institute of Quantum Optics
Leibniz Universität Hannover und
German National Metrology Institute (PTB), Braunschweig
Welfengarten 1
30167 Hannover, GERMANY
phone: +49 511 762-17644
e-Mail: christian.ospelkaus@iqo.uni-hannover.de

PD Dr. Wolfgang Quint
GSI Helmholtzzentrum für Schwerionenforschung GmbH
Planckstr. 1
64291 Darmstadt, GERMANY
phone: +49 6159 712141
e-mail: w.quint@gsi.de
https://www.gsi.de/en/

Related links:
http://base.web.cern.ch/ – BASE: Baryon Antibaryon Symmetry Experiment
http://ulmerfsl.riken.jp/index.html – Ulmer Fundamental Symmetries Laboratory

Weitere Informationen:

http://www.uni-mainz.de/presse/aktuell/101_ENG_HTML.php – press release "Magnetic moment of a single antiproton determined with greatest precision ever" (19 Jan. 2017)
http://www.uni-mainz.de/presse/17364_ENG_HTML.php – press release "Magnetic moment of the proton measured with unprecedented precision" (6 June 2014)
http://www.uni-mainz.de/presse/14236_ENG_HTML.php – press release "Quantum leap: Magnetic properties of a single proton directly observed for the first time" (21 June 2011)

Petra Giegerich | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>