Seminarium Fizyki Jądra Atomowego

At the dawn of the Universe, an imbalance between the amounts of matter and antimatter led to the matter - dominated cosmos we observe today. The origin of this asymmetry remains one of the key open questions in modern physics. High-energy nuclear collisions recreate conditions similar to those that existed microseconds after the Big Bang, producing comparable quantities of matter and antimatter. A significant fraction of the created antimatter escapes annihilation in the rapidly expanding fireball, making such collisions a powerful experimental tool for generating heavy antimatter nuclei and studying their properties. In this seminar, we present the observation of the heaviest antimatter hypernucleus detected to date. The discovery was achieved through the identification of its two-body decay, following its production in ultrarelativistic heavy-ion collisions by the STAR experiment at the Relativistic Heavy Ion Collider. The measured lifetimes of antihypernuclei are compared with those of their matter counterparts, providing a test of matter - antimatter symmetry. Additionally, production yield ratios of (anti)hypernuclei and (anti)nuclei are evaluated and confronted with theoretical model predictions, offering new insights into their production mechanisms and the underlying physics of baryon - antibaryon asymmetry.