What is the use of the 5th dimension

29.01.2021 09:57

Through the fifth dimension to dark matter

Dr. Renée Dillinger-Reiter Communication and press
Johannes Gutenberg University Mainz

A discovery in theoretical physics could help solve the mystery of dark matter

Theoretical physicists from the PRISMA⁺ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU) are working on a theory that goes beyond the standard model of particle physics and can answer questions for which the standard model has to fit - for example with regard to the masses of elementary particles or existence of dark matter. The central element of the theory is an extra dimension in space-time. So far, the scientists were faced with the problem that the predictions of their theory could not be verified experimentally. They have now solved this problem and published their results in the current issue of the European Physical Journal C.

As early as the 1920s, Theodor Kaluza and Oskar Klein speculated, on the occasion of their search for a unified theory of gravity and electromagnetism, that in addition to the three spatial dimensions and time we are familiar with from everyday life - summarized in the four-dimensional space-time of physics - there are others Could give room dimensions. However, these would be tiny and imperceptible to humans. This idea experienced a remarkable renaissance in the late 1990s when it was realized that the existence of a fifth dimension could answer some of the open questions of particle physics. For example, Yuval Grossman from Stanford University and Matthias Neubert, at the time professor at Cornell University in the USA, showed in a highly regarded work that by embedding the standard model of particle physics in a five-dimensional space-time, the previously mysterious patterns in the Masses of known elementary particles can be explained.

Another 20 years later, the group around Matthias Neubert, who has been researching and teaching at Johannes Gutenberg University in Mainz since 2006 and is spokesman for the PRISMA + Cluster of Excellence there, made another unexpected discovery: They found out that the five-dimensional field equations indicate the existence of a new one Predict a heavy particle that should behave similarly to the Higgs boson of the Standard Model, but whose mass is many times heavier - so difficult that it cannot be produced or detected even at the world's largest particle accelerator LHC at the European Research Center CERN near Geneva . “It was bewitched. We were enthusiastic about the idea that our theory predicts the existence of a new elementary particle, but we didn't have the opportunity to test this hypothesis experimentally in the foreseeable future, ”remembers Javier Castellano Ruiz, who as a doctoral student in Mainz played a key role in the theoretical research is.

The detour via the fifth dimension

In their latest publication in the renowned European Physical Journal C, the physicists have now found a spectacular way out of this dilemma. They discovered that the new particle they postulated inevitably mediates an interaction between the known elementary particles and the mysterious dark matter in the universe. Even the amount of dark matter observed, which was determined from astrophysical observations, can be explained in terms of their theory. This opens up interesting new possibilities for the search for the building blocks of dark matter - via the detour through the fifth dimension, so to speak - as well as insights into the early history of the universe during which dark matter was produced. “After years of searching intensively for possible confirmations of our theoretical predictions, we are now confident that the mechanism we have discovered will explain dark matter and help to prove it experimentally. Because the properties of the interaction between visible and dark matter - mediated by the particle we postulated - are precisely predicted by the theory, ”says Matthias Neubert, head of the research team. “Ultimately - according to our idea - the new particle will initially not be able to be detected directly, but via its interaction.” The example shows in a very nice way how experimental and theoretical basic research can complement each other - a trademark of the PRISMA⁺ Cluster of Excellence in Mainz.

Scientific contact:

Prof. Dr. Matthias Neubert
Director of the Mainz Institute for Theoretical Physics (MITP) / Spokesperson for the PRISMA + Cluster of Excellence
Johannes Gutenberg University Mainz
55099 Mainz
Email: [email protected]

Original publication:

A. Carmona, J. Castellano, M. Neubert, A warped scalar portal to fermionic dark matter,
Eur. Phys. J. C 81, 58 (2021) [arXiv: 2011.09492]
DOI: 10.1140 / epjc / s10052-021-08851-0

Additional Information:


Features of this press release:
Physics / astronomy
research results