The "up antiquark" is a fundamental particle that is part of the Standard Model of particle physics. It is the antimatter counterpart of the up quark, which is one of the building blocks of protons and neutrons. The up antiquark has a positive electric charge and is represented by the symbol \baru . Antiquarks, including the up antiquark, combine with quarks to form hadrons, such as mesons and baryons. In a meson, an up antiquark pairs with a down quark or another type of quark. Understanding antiquarks helps scientists explore the properties of matter and antimatter in the universe.