The existence of antimatter is a well-established concept in physics. Antimatter particles are essentially counterparts to ordinary matter particles, with opposite electric charge and other quantum properties. When a particle and its corresponding antiparticle come into contact, they can annihilate each other, converting their mass into energy.
The reason we observe an asymmetry between matter and antimatter in the observable universe is still an open question in physics. This puzzle is known as the baryon asymmetry problem. While particles and antiparticles are produced in pairs, it appears that the early universe had a slight excess of matter over antimatter. This small imbalance allowed matter to dominate as the universe expanded and cooled.
Scientists are actively researching the origins of this matter-antimatter asymmetry. Various theories and experiments are exploring processes that could have contributed to the observed baryon asymmetry, such as violations of charge-parity (CP) symmetry, which refers to the combined operation of charge conjugation (C, which transforms particles into their antiparticles) and parity transformation (P, which flips the spatial coordinates).
While the exact mechanism behind the matter-antimatter asymmetry remains a subject of ongoing scientific investigation, it's important to note that antimatter does exist and is produced in various contexts, such as high-energy particle accelerators and certain astrophysical phenomena. However, in the observable universe, ordinary matter is predominant.