CERN’s Large Hadron Collider finds the heaviest antimatter particle yet

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Yeah! Science! Scientists at the CERN Large Hadron Collider – the most powerful particle accelerator ever built – have detected the heaviest form of antimatter observed. This discovery is as important as CERN’s previous breakthroughs, like the Higgs Boson particle, B-meson decay, and hypernuclei.

Scientists from the ALICE (A Large Ion Collider Experiment) at CERN’s Large Hadron Collider reported evidence of a new antimatter particle called antihyperhelium-4, essentially the “evil twin” of another weird particle called hyperhelium-4. This incredibly exotic form of matter contains two antiprotons, an antineutron, and an unstable particle called an antilambda comprised of subatomic quarks.

This discovery is important because it allowed physicists to study the extreme conditions of the cosmos when it was less than a second old. It also gives us insights into one of our biggest mysteries: the baryon asymmetry problem.

When the universe burst into existence during the Big Bang, matter and antimatter should have existed in equal amounts. Since the opposing pairs always annihilate each other, all matter and antimatter should have converted into pure energy. Somehow, we ended up with a universe dominated by regular matter, with just a tiny bit of antimatter surviving. Studying hyperhelium and its antimatter twin could help unlock this puzzle.

The discovery of antihyperhelium-4 resulted from a collision experiment performed with the LHC in 2018. It slammed together lead ions at stupendous speeds, recreating the hyper-hot conditions of the newborn universe. Researchers then used a cutting-edge machine learning model to study the data from the collision. The analysis spotted the signature of antihyperhelium-4 particles as they decayed into other particles.

Also spotted was the lighter antihyperhydrogen-4. The researchers precisely measured the masses of these two particles and were able to match the data with the most current physics theories. The experiment’s results confirm that matter and antimatter are created in equal portions. So, what tipped the balance if the universe started with level proportions?

Physicists are still without adequate answers. However, the LHC receives occasional upgrades, like the one that installed supersized magnets for sharper beams earlier this month. Who knows what new antimatter extremes may emerge next?