Researchers have uncovered the complex structure of the carbon-12 nucleus and found that its low-energy state consists of clusters of atoms forming triangles. The discovery, made by an international collaboration, deepens our understanding of how carbon formed in the universe and is consistent with existing experimental data.
An international study has revealed the structure of triangular clusters within the nucleus of carbon-12 atoms, providing important clues to our understanding of the origin and abundance of carbon in the universe.
The element carbon is essential to organic chemistry and life as we know it. The physical properties of its most common isotope, carbon-12, are extremely complex. Many experimental and theoretical studies have been devoted to determining the energy and fundamental structure of the carbon-12 nuclear state.
In this work, the researchers calculated these states from first principles - the most basic building blocks of physical theories. This method uses supercomputers and nuclear lattice simulations to calculate the three-dimensional shapes formed by the protons and neutrons that make up the nucleus. The results show that all low-energy states of carbon-12 have a substructure in which six protons and six neutrons are aggregated into alpha particles. Alpha particles are helium-4 nuclei containing two protons and two neutrons.
The Hoyle state: a window for stellar carbon production
A well-known nuclear state of carbon-12 is the Hoyle state. The energy of this state is close to the energy threshold of three alpha particles or helium nuclei. This energy therefore greatly contributes to the production of carbon in helium-burning stars. This helps explain the presence of carbon in the universe.
The results of this study show that the Hoyle state consists of a "curved arm" or blunt triangular arrangement of alpha particles. All low-energy states of carbon-12 have an intrinsic shape of an equilateral or obtuse triangle consisting of three alpha particles. The new results provide information about the possible geometries of the nuclear states.
Global collaboration to reveal carbon-12 nuclear structure
Carbon atoms are the building blocks of complex organic chemistry that form the building blocks of life. The nuclear physics of carbon-12, the main isotope of the carbon atom, is also fraught with complexity. Researchers from the University of Bonn, the Jülich Research Center in Germany, the Islamic University of Science and Technology in Gaziantep, Turkey, the Graduate School of the China Academy of Engineering Physics, Tbilisi State University, and the Rare Isotope Beam Facility at Michigan State University calculated the nuclear state structure of carbon-12 using the abinitio framework of nuclear lattice effective field theory.
The geometric mysteries of carbon-12 and the origin of the universe
The study found that all low-lying states of carbon-12 have an intrinsic shape, consisting of three alpha clusters forming an equilateral triangle or an obtuse triangle. The equilateral triangle state also has a dual description of particle-hole excitations in the mean field diagram.
The results are consistent with experimental data and provide the first model-independent density of states map of carbon-12 nuclei. The results help explain how carbon originated from helium and hydrogen shortly after the Big Bang.
Compiled source: ScitechDaily