In particle physics, corresponding to most kinds of particles there is an associated antiparticle. An antiparticle has the same mass and opposite charge (including electric charge). For example, for every quark there is a corresponding type of antiparticle. The antiquarks have the same mass, mean lifetime, and spin as their respective quarks, but the electric charge and other charges have the opposite sign. Up-type antiquarks have charges of −2⁄3 e and down-type antiquarks have charges of +1⁄3 e. Since the electric charge of a hadron is the sum of the charges of the constituent quarks, all hadrons have integer charges.