B-mesons are subatomic particles made up of a bottom quark and an antiquark. They are part of the larger family of particles known as mesons, which are composed of a quark and an antiquark. B-mesons come in several varieties, including B^0, B^+, and B_s mesons, each differing in their specific quark composition. These particles are important in the study of particle physics and CP violation, which helps scientists understand the differences between matter and antimatter. B-mesons are produced in high-energy collisions, such as those occurring in particle accelerators like the Large Hadron Collider.