K⁰, or neutral kaon, is a type of subatomic particle that belongs to the family of mesons. It is composed of a quark and an antiquark, specifically a down quark and an anti-strange quark. K⁰ particles are important in the study of particle physics and help scientists understand the behavior of matter and antimatter. K⁰ particles can exist in two different states, known as K₁ and K₂, which can oscillate into each other. This phenomenon is a key aspect of quantum mechanics and has implications for CP violation, a concept that explains why the universe has more matter than antimatter.