Mirror image: Fundamental symmetry in nature confirmed using CERN Large Collider

A general view of the Large Hadron Collider © Pierre Albouy
The existence of a fundamental symmetry in nature has been confirmed by measuring particle mass and electric charge using the CERN Large Hadron Collider. Researchers say it will help determine which theory on the laws of the universe is most plausible.

The study, conducted by researchers at Brazil's São Paulo University (USP) and the University of Campinas, determined that there is a symmetry between the nuclei of particles and their antiparticles in terms of charge, parity, and time. The research was published in the journal Nature Physics. 

The experiment was part of an investigation to detect differences between the ways in which protons and neutrons join in nuclei while their antiparticles form antinuclei.

"After the Big Bang, for every particle of matter an antiparticle was created. In particle physics, a very important question is whether all the laws of physics display a specific kind of symmetry known as CPT, and these measurements suggest that there is indeed a fundamental symmetry between nuclei and antinuclei," said Marcelo Gameiro Munhoz, a professor at USP's Physics Institute (IF), as quoted by Phys.org.

The measurements were made possible by ALICE (A Large Ion Collider Experiment), a heavy-ion detector on the Large Hadron Collider (LHC) ring. It measured particles produced in high-energy collisions of heavy ions in the LHC. This process allows for the study of matter at extremely high temperatures and densities.

The collisions were found to produce a large number of particles and antiparticles, producing nuclei and antinuclei at nearly the same rate. Using this data, ALICE was able to make a detailed comparison of the properties of nuclei and antinuclei that were most abundantly produced.

After measuring both the curvature of particle tracks in the detector's magnetic field and the particles' time of flight, that information was then used to determine the mass-to-charge ratios for nuclei and antinuclei.

Munhoz believes the finding can help physicists determine which of the theories on the fundamental laws of the universe is most plausible.

"These laws describe the nature of all matter interactions," he said, "so it's important to know that physical interactions aren't changed by particle charge reversal, parity transformation, reflections of spatial coordinates and time inversion. The key question is whether the laws of physics remain the same under such conditions."

The existence and relationship between matter and anti-matter has long stumped scientists who believe, based on existing theories, that the Big Bang should have produced equal amounts of both, which would have resulted in the two immediately destroying each other.