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 Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)

nachricht Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory

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: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>