K-mesons, also known as kaons, are a type of subatomic particle that belong to the meson family. They are composed of a quark and an antiquark, specifically a strange quark and either an up or down quark. K-mesons come in several varieties, including K+, K-, and K0, each with different properties and charges. K-mesons are important in particle physics because they help scientists study the weak force, one of the four fundamental forces in nature. They are also involved in processes that lead to CP violation, which is a difference in behavior between matter and antimatter, providing insights into the imbalance of the universe.