CERN detects first matter-antimatter imbalance in subatomic particles

Physicists at CERN have reported the first observations of matter-antimatter imbalance in a subatomic particle 'baryon', offering clues as to why matter dominates in the universe.

Particles of antimatter -- called 'antiparticles' -- have the same mass as particles of matter but an opposite charge.

According to particle physics models, matter and antimatter should have been created in equal amounts following the Big Bang. However, research indicates a significant imbalance, with matter dominating over antimatter. Understanding why the universe favours matter is one of the most profound questions in physics.

The Standard Model of particle physics -- currently the leading model, as it is said to provide the best explanation about the fundamental nature of matter -- predicts that matter and antimatter behave differently.

The model theoretically predicts that when a particle is replaced with an antiparticle and its position in space is mirrored, the laws of physics are violated. This violation is referred to as 'charge-parity' (CP) violation.

Previously, CP violation was observed in mesons a type of subatomic particle that weighs between an electron and a proton. These observations were first documented over 60 years ago.

In a recent paper published in the journal Nature, researchers from the Large Hadron Collider beauty (LHCb) Collaboration at the European Organization for Nuclear Research (CERN), Switzerland, have, for the first time, observed this violation in baryons, of which protons and neutrons are types.

Specifically, the violation was noted in a baryon that decayed into a proton and mesons.

The authors of the study stated, "These observations demonstrate the different behaviours of baryons and antibaryons." This finding is significant as baryons constitute most of the matter in the observable universe.

"This discovery opens a new path in the search for physics beyond the Standard Model," the team wrote.

For the study, the researchers analysed data collected from proton-proton collisions at the Large Hadron Collider -- the world's largest and most powerful particle accelerator located at CERN.

"The (charge-parity violation) reveals a difference in behaviour between baryonic matter and antimatter," the authors wrote.

"While such a violation was predicted and does not resolve the Big Bang matter-antimatter imbalance, finding out the details of this violation experimentally will offer important clues, opening up opportunities for further theoretical and experimental studies of the nature of (charge-parity) violation," they added.

It is said that matter and antimatter can interact and destroy each other in a process called 'annihilation', converting all the mass into 'radiant energy' -- which is energy that exists in the absence of matter.