A B-meson is a type of subatomic particle made up of a bottom quark and a light antiquark, such as an up antiquark or a down antiquark. B-mesons are part of the larger family of particles known as mesons, which are composed of a quark and an antiquark. They play a crucial role in the study of particle physics and the Standard Model. B-mesons are particularly interesting because they can oscillate between different states, a phenomenon known as B-meson mixing. This property allows physicists to explore the differences between matter and antimatter, contributing to our understanding of the universe's evolution. Their decay processes are also studied to investigate CP violation, which helps explain why the universe is predominantly composed of matter.