Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Reveal Structure of Carbon’s ‘Hoyle State’

11.12.2012
A North Carolina State University researcher has taken a “snapshot” of the way particles combine to form carbon-12, the element that makes all life on Earth possible. And the picture looks like a bent arm.

Carbon-12 can only exist when three alpha particles, or helium-4 nuclei, combine in a very specific way. This combination is known as the Hoyle state. NC State physicist Dean Lee and German colleagues Evgeny Epelbaum, Hermann Krebs and Ulf-G.


Alpha clusters in the Carbon-12 nucleus forming a "bent arm" shape.

Meissner had previously confirmed the existence of the Hoyle state using a numerical lattice that allowed the researchers to simulate how the protons and neutrons interact. When the researchers ran their simulations on the lattice, the Hoyle state appeared together with other observed states of carbon-12, proving the theory correct from first principles.

But they also wanted to find out how the nucleons (the protons and neutrons inside the nucleus of an atom) were arranged inside the nucleus of carbon-12. This would enable them to “see” the structure of the Hoyle state. Using the same lattice, the researchers, along with collaborator Timo Laehde, found that carbon-12’s six protons and six neutrons formed three “alpha clusters” of four nucleons each. At low energy, the alpha clusters tended to clump together in a compact triangular formation. But for the Hoyle state, which is an excited energy state, the three alpha clusters combined in a “bent arm” formation.

The researchers’ findings will appear this month in Physical Review Letters.

“It’s interesting that a straight chain seems not to be the preferred configuration for the Hoyle state,” Lee says. “A bend in the chain seems necessary. This work leads us to the question of what other nuclei have such alpha cluster shapes. These would be rather exotic structures in nuclear physics and open some really interesting questions regarding shape and stability. For example, can we have longer chains of alpha clusters? We are investigating these possibilities.”

The work was funded by the U.S. Department of Energy; the Deutsche Forschungsgemeinschaft, Helmholtz-Gemeinschaft Deutscher Forschungszentren, and Bundesministerium fuer Bildung und Forschung in Germany; European Union HadronPhysics3 Project and the European Research Council; and the National Natural Science Foundation of China. Computational resources were provided by the Juelich Supercomputing Center. The NC State Department of Physics is part of the College of Physical and Mathematical Sciences.

-peake-

Note to editors: an abstract of the paper follows.

“Structure and Rotations of the Hoyle State”

Authors: Dean Lee, North Carolina State University; Evgeny Epelbaum and Hermann Krebs, Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, Germany; Timo A. Laehde, Forschungszentrum Juelich, Germany; Ulf-G. Meissner, Helmholtz-Institut fuer Strahlen-und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, Germany

Published: Physical Review Letters

Abstract:

The excited state of the 12C nucleus known as the “Hoyle state” constitutes one of the most interesting, difficult and timely challenges in nuclear physics, as it plays a key role in the production of carbon via fusion of three alpha particles in red giant stars. In this letter, we present ab initio lattice calculations which unravel the structure of the Hoyle state, along with evidence for a low-lying spin-2 rotational excitation. For the 12C ground state and the first excited spin-2 state, we find a compact triangular configuration of alpha clusters. For the Hoyle state and the second excited spin-2 state, we find a “bent-arm” or obtuse triangular configuration of alpha clusters. We also calculate the electromagnetic transition rates between the low-lying states of 12C.

Tracey Peake | EurekAlert!
Further information:
http://www.ncsu.edu

Further reports about: Carbon’s Hoyle Physic alpha particles protein structures

More articles from Physics and Astronomy:

nachricht Fast and Accurate 3-D Imaging Technique to Track Optically-Trapped Particles
24.04.2015 | Korea Advanced Institute of Science and Technology

nachricht Tau Ceti: The next Earth? Probably not
23.04.2015 | Arizona State University

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: Fast and Accurate 3-D Imaging Technique to Track Optically-Trapped Particles

KAIST researchers published an article on the development of a novel technique to precisely track the 3-D positions of optically-trapped particles having complicated geometry in high speed in the April 2015 issue of Optica.

Daejeon, Republic of Korea, April 23, 2015--Optical tweezers have been used as an invaluable tool for exerting micro-scale force on microscopic particles and...

Im Focus: NOAA, Tulane identify second possible specimen of 'pocket shark' ever found

Pocket sharks are among the world's rarest finds

A very small and rare species of shark is swimming its way through scientific literature. But don't worry, the chances of this inches-long vertebrate biting...

Im Focus: Drexel materials scientists putting a new spin on computing memory

Ever since computers have been small enough to be fixtures on desks and laps, their central processing has functioned something like an atomic Etch A Sketch, with electromagnetic fields pushing data bits into place to encode data.

Unfortunately, the same drawbacks and perils of the mechanical sketch board have been just as pervasive in computing: making a change often requires starting...

Im Focus: Exploding stars help to understand thunderclouds on Earth

How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was discovered, more or less by coincidence, that cosmic rays provide suitable probes to measure electric fields within thunderclouds. This surprising finding is published in Physical Review Letters on April 24th. The measurements were performed with the LOFAR radio telescope located in the Netherlands.

How is lightning initiated in thunderclouds? This is difficult to answer - how do you measure electric fields inside large, dangerously charged clouds? It was...

Im Focus: On the trail of a trace gas

Max Planck researcher Buhalqem Mamtimin determines how much nitrogen oxide is released into the atmosphere from agriculturally used oases.

In order to make statements about current and future air pollution, scientists use models which simulate the Earth’s atmosphere. A lot of information such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

HHL Energy Conference on May 11/12, 2015: Students Discuss about Decentralized Energy

23.04.2015 | Event News

“Developing our cities, preserving our planet”: Nobel Laureates gather for the first time in Asia

23.04.2015 | Event News

HHL's Entrepreneurship Conference on FinTech

13.04.2015 | Event News

 
Latest News

Electrons Move Like Light in Three-Dimensional Solid

24.04.2015 | Materials Sciences

Connecting Three Atomic Layers Puts Semiconducting Science on Its Edge

24.04.2015 | Materials Sciences

Understanding the Body’s Response to Worms and Allergies

24.04.2015 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>