Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Surprise to physicists – protons aren’t always shaped like a basketball

07.04.2003


When Gerald A. Miller first saw the experimental results from the Thomas Jefferson National Accelerator Facility, he was pretty sure they couldn’t be right. If they were, it meant that some long-held notions about the proton, a primary building block of atoms, were wrong.



But in time, the findings proved to be right, and led physicists to the conclusion that protons aren’t always spherically shaped, like a basketball.

"Some physicists thought they did the experiment wrong," said Miller, a University of Washington physics professor. "Even I thought so initially. And then I remembered that it looked like something else I thought was wrong – our own conclusion in 1995."


In fact, by 1996 he and two colleagues were ready to publish a paper theorizing the angles at which protons would bounce off electrons after collisions in a nuclear accelerator. The measurements would tell a lot about protons’ internal electric and magnetic properties, and virtually everyone expected the two effects to cause the same kinds of collisions. But the 1996 paper described collisions that were quite different.

Miller was sure he and his colleagues had gotten it wrong somehow – until he saw the results of the actual experimental work at Jefferson, a national laboratory in Newport News, Va. Researchers at Jefferson published their initial results in 2000 and updated their findings last year.

What Miller discovered from those results is that a proton at rest can be shaped like a ball – the expected shape and the only one described in physics textbooks. Or it can be shaped like a peanut, like a rugby ball or even something similar to a bagel.

He was able to use his model to predict the behavior of quarks, and he discovered that different effects of the quarks could change the proton’s shape. The model showed that the highest-momentum quarks, those moving nearly at light speed inside the proton, produced the peanut shape.

"The quarks are like prisoners walking around in a jail cell. They just are walking very fast, and when they come to a wall they have to turn around and we can see that, indirectly, and measure it," Miller said.

If the quarks are moving more slowly, the surface indentations of the peanut shape fill in and the proton takes on a form something like a rugby ball, or a beehive. The slowest quarks produce the spherical shape that physicists generally expected to see. Another shape – a flattened round form like a bagel – is sort of a cousin to the peanut shape with the high-momentum quarks. In the peanut shape, the quarks spin in the same direction as the proton, while in the bagel shape they spin in the opposite direction as the proton.

The variety of shapes is nearly limitless and depends on the speed of the quarks inside the proton and what direction they are spinning, said Miller, who presents his findings today (April 5) during a news conference and an invited talk at the American Physical Society meeting in Philadelphia.

The Jefferson results, he said, are a small piece of the puzzle for physicists who are trying to unify the four forces of nature – gravity, electromagnetic, strong and weak – into a "theory of everything" by which they can understand the form and function of all matter. Taking this step, Miller said, allows physicists to make better predictions so other experiments can get even closer to a unified theory, and it provides clues for how to devise those experiments.

The first implication of the Jefferson findings, he said, is that "a bunch of textbooks will have to have some of their pages updated."

Beyond that, he said, it isn’t clear right now whether there will be practical implications. However, he tells the story of Michael Faraday, who presented findings in the 1830s on electromagnetic induction but was at a loss to explain the value of his findings. Yet today, the principles he developed are responsible for all the electric generators sending juice from power stations.

"You just never know until you understand something where it might lead," Miller said.


For more information, contact Miller at (206) 543-2995 or miller@phys.washington.edu

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Physics and Astronomy:

nachricht Beyond the brim, Sombrero Galaxy's halo suggests turbulent past
21.02.2020 | NASA/Goddard Space Flight Center

nachricht 10,000 times faster calculations of many-body quantum dynamics possible
21.02.2020 | Christian-Albrechts-Universität zu Kiel

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: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Active droplets

21.02.2020 | Medical Engineering

Finding new clues to brain cancer treatment

21.02.2020 | Health and Medicine

Beyond the brim, Sombrero Galaxy's halo suggests turbulent past

21.02.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>