antikvarks

Antiquarks are the antiparticles of quarks. Just as a positron is the antiparticle of an electron, an antiquark has the same mass as its corresponding quark but opposite electric charge, baryon number, strangeness, charm, bottomness, and topness. For example, the antiquark of an up quark (which has a charge of +2/3) is an anti-up quark with a charge of -2/3. Similarly, an anti-down quark has a charge of +1/3, opposing the down quark's -1/3 charge.

Antiquarks, like quarks, are fundamental particles that are not made up of smaller components. They combine to form antibaryons, which are the antiparticles of baryons. For instance, an antiproton is composed of two anti-up quarks and one anti-down quark, whereas a proton is made of two up quarks and one down quark. When a quark and its corresponding antiquark meet, they can annihilate each other, producing energy in the form of photons or other particle-antiparticle pairs. The existence of antiquarks was first theorized by physicist Paul Dirac in his relativistic theory of the electron.