New and surprising duality discovered in theoretical particle physics

On the left side we have a diffusion process involving two gluons (green/yellow and blue/cyan) interacting to produce a gluon (red/magenta) and a Higgs particle (white). The more complex scattering process on the right is mirrored by the simpler one on the left, but here we have a scattering process of two gluons (green/yellow and blue/cyan) interacting to produce four gluons (red/magenta, red/yellow , blue/magenta and green/cyan). The black color symbolizes that in the collision itself many different elemental interactions can occur, and we have to add up all the possibilities. According to Heisenberg’s uncertainty principle, we cannot know exactly which possibility has occurred, so it is a “black box”. Credit: Søren J. Granat

A new and surprising duality has been discovered in theoretical particle physics. The duality exists between two types of scattering processes that can occur in proton collisions performed in the Large Hadron Collider at CERN in Switzerland and France. The fact that this connection can, surprisingly, be made indicates that there is something about the intricate details of the Standard Model of particle physics that is not fully understood. The Standard Model is the model of the world at the subatomic scale that explains all the particles and their interactions, so when surprises appear, there is reason to pay attention. The scientific article is now published in Physical examination letters.

Duality in physics

The concept of duality appears in different areas of physics. The best known duality is probably the particle-wave duality in quantum mechanics. The famous double slit experiment shows that light behaves like a wave, while Albert Einstein received his Nobel Prize for showing that light behaves like a particle.

What is strange is that the light is in fact both and neither at the same time. There are simply two ways to look at this entity, light, and each comes with a mathematical description. Both with a completely different intuitive idea, but still describe the same thing.

“What we have now found is a similar duality,” says Matthias Wilhelm, assistant professor at the Niels Bohr International Academy. “We calculated the prediction for a diffusion process and for another diffusion process.

Our current calculations are less experimentally tangible than the famous double slit experiment, but there is a clear mathematical map between the two, and it shows that they both contain the same information. They’re related, in a way.”

Theory and experiments go hand in hand

The Large Hadron Collider collides with a lot of protons – in those protons there are a lot of smaller particles, the subatomic gluons and quarks.

During the collision, two different proton gluons can interact and new particles are created, such as the Higgs particle, resulting in complex patterns in the detectors.

Researchers map what these patterns look like, and the theoretical work done in relation to the experiments aims to describe precisely what is happening in mathematical terms, in order to create an overall formulation, as well as to make predictions that can be compared to results of the experiments.

“We calculated the diffusion process for two gluons interacting to produce four gluons, as well as the diffusion process for two gluons interacting to produce a gluon and a Higgs particle, both in a slightly simplified version of the Standard Model. To our surprise, we found that the results of these two calculations are related. A classic case of duality. In a way, the answer to the probability that a diffusion process occurs carries with it the answer to the probability that another scattering process to occur. The strange thing about this duality is that we don’t know why this relationship between the two different scattering processes exists. We mix two very different physical properties of the two predictions, and we see the relationship , but it’s still a bit of a mystery where the connection is,” says Matthias Wilhelm.

The principle of duality and its application

According to current understanding, the two should not be related, but with the discovery of this startling duality, the only correct way to respond to it is to investigate further.

Surprises always mean that there is something we now know that we don’t understand. After the discovery of the Higgs particle in 2012, no new sensational particles have been discovered. The way we hope to detect new physics now is to make very precise predictions of what we expect, then compare them with very precise measurements of what nature is showing us, and see if we can find any deviations there. .

We need a lot of precision, both experimentally and theoretically. But with more precision comes more difficult calculations. “So where that might lead is to work to see if this duality can be used to derive some sort of ‘mileage’ from it, because one calculation is simpler than the other – but it still gives the answer. to the most complicated calculation,” says Matthias Wilhelm.

“So if we can get away with using simple math, we can use duality to answer the question that would otherwise require more complicated math – But then we really have to understand duality. It’s important to note, however, that we’re not. But usually the questions that arise from the unexpected behavior of things are much more interesting than an orderly, expected outcome.

For the first time, scientists rigorously calculate three-particle scattering from theory

More information:
Lance J. Dixon et al, Folding amplitudes into form factors: an antipodal duality, Physical examination letters (2022). DOI: 10.1103/PhysRevLett.128.111602

Provided by the Niels Bohr Institute

Quote: New and surprising duality discovered in theoretical particle physics (2022, April 25) retrieved on April 25, 2022 from

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