Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Strange’ physics experiment is unraveling structure of proton

20.06.2005


An international team of nuclear physicists has determined that particles called strange quarks do, indeed, contribute to the ordinary properties of the proton.



Quarks are subatomic particles that form the building blocks of atoms. How quarks assemble into protons and neutrons, and what holds them together, is not clearly understood. New experimental results are providing part of the answer.

The experiment, called G-Zero, was performed at Thomas Jefferson National Accelerator Facility in Newport News, Va. Designed to probe proton structure, specifically the contribution of strange quarks, the experiment has involved an international group of 108 scientists from 19 institutions. Steve Williamson, a physicist at the University of Illinois at Urbana-Champaign, is the experiment coordinator.


"The G-Zero experiment provided a much broader view of the small-scale structure of the proton," said Doug Beck, a physicist at Illinois and spokesman for the experiment. "While our results agree with hints from previous experiments, the new findings are significantly more extensive and provide a much clearer picture."

Beck will present the experimental results at a seminar at the Jefferson facility Friday morning. Also on Friday, the researchers will submit a paper describing the results to the journal Physical Review Letters. The paper will be posted on the physics archive (under "nuclear experiment") at www.arxiv.org.

The centerpiece of the G-Zero experiment is a doughnut-shaped superconducting magnet 14 feet in diameter that was designed and tested by physicists at Illinois including Ron Laszewski, now retired. The 100,000-pound magnet took three years to build.

In the experiment, an intense beam of polarized electrons was scattered off liquid hydrogen targets located in the magnet’s core. Detectors, mounted around the perimeter of the magnet, recorded the number and position of the scattered particles. The researchers then used mathematical models to retrace the particles’ paths to determine their momenta.

"There is a lot of energy inside a proton," Beck said. "Some of that energy can change back and forth into particles called strange quarks." Unlike the three quarks (two "up" and one "down") that are always present in a proton, strange quarks can pop in and out of existence.

"Because of the equivalence of mass and energy, the energy fields in the proton can sometimes manifest themselves as these ’part-time’ quarks," Beck said. "This is the first time we observed strange quarks in this context, and it is the first time we measured how often this energy manifested itself as particles under normal circumstances."

The results are helping scientists better understand how one of the pieces of the Standard Model is put together. The Standard Model unifies three forces: electromagnetism, the weak nuclear interaction and the strong nuclear interaction.

"The G-Zero experiment tells us more about the strong interaction -- how protons and neutrons are held together," Beck said. "However, we still have much to learn."

James E. Kloeppel | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

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: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>