Gaining knowledge by simplification

June 2, 2017, Technische Universitat Darmstadt
Nuclei start off from a simple approximate description (“leading order (LO)”, on the left) and move to their correct physical “places” by systematic corrections (“next-to-leading order (NLO)” and further). Credit: König / Hammer

The "strong force" plays a crucial role for the existence of matter in the visible universe. Scientists at TU Darmstadt are carrying out research in that field and recently published their results in Physical Review Letters. To describe the processes in the nucleus they used a method of theoretical simplification which might be applicable to heavier nuclei.

The recent publication concerns the so-called "" that plays a crucial role for the existence of matter in the . Just how exactly this mechanism, fundamentally described by the theory of Quantum Chromodynamics as the interaction between quarks and gluons (elementary particles that can however not be observed in isolation), brings about the force that binds protons and neutrons together in is still a matter of active research.

The scientists made use of an important concept in modern theoretical physics: effective field theories. Simply put, such theories boil down microscopic details to their essential content by tailoring the mathematical formalism to the level of detail one aims to describe. This approach can be interpreted as choosing an appropriate "theoretical resolution," much like screens that are watched only from a large distance can have much larger pixels than a smartphone to ensure the same visual impression.

Looking from a distance can in fact enable one to see more, i.e., the famous "bigger picture". In this case, this means starting the description of nuclei with something very simple: in what is known as the "unitarity limit," systems of protons and neutrons exhibit universal behavior which they share with seemingly very different particles like atoms in ultracold gases. In this limit, a single parameter, related to the interaction between three particles, governs the physical properties of observed states. The scientists show that indeed atomic up to four constituents (i.e., helium) can be well approximated by this simple limit, and that it is possible to systematically increase the theoretical resolution by calculating a sequence of corrections.

This way, a good description of experimentally observed binding energies is achieved with a minimum number of information used as input. The scientists involved conjecture that this approach can also be useful to describe heavier elements.

Explore further: New method to better understand atomic nuclei

More information: Sebastian König et al. Nuclear Physics Around the Unitarity Limit, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.202501

Related Stories

New method to better understand atomic nuclei

September 24, 2015

The precise structure of atomic nuclei is an old problem that has not been fully solved yet, and it also constitutes a current research focus in the field of natural sciences. Together with colleagues from Bonn University, ...

New CERN results show novel phenomena in proton collisions

April 25, 2017

In a paper published today in Nature Physics , the ALICE collaboration reports that proton collisions sometimes present similar patterns to those observed in the collisions of heavy nuclei. This behaviour was spotted through ...

Recommended for you

Muons spin tales of undiscovered particles

April 20, 2018

Scientists at U.S. Department of Energy (DOE) national laboratories are collaborating to test a magnetic property of the muon. Their experiment could point to the existence of physics beyond our current understanding, including ...

Integrating optical components into existing chip designs

April 19, 2018

Two and a half years ago, a team of researchers led by groups at MIT, the University of California at Berkeley, and Boston University announced a milestone: the fabrication of a working microprocessor, built using only existing ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.