Murray Gell-Mann quarks for Muster Mark!" book 2, episode 4). Zweig had referred to the particles as "aces", but Gell-Mann's name caught on. Quarks, antiquarks, and gluons were soon established as the underlying elementary objects in the study of the structure of hadrons. He was awarded a Nobel Prize in physics in 1969 for his contributions and discoveries concerning the classification of elementary particles and their interactions. In 1972 he and Harald Fritzsch introduced the conserved quantum number "color charge", and later, together with Heinrich Leutwyler, they coined the term quantum chromodynamics (QCD) as the gauge theory of the strong interaction. The
Elementary particle by its omission of gravitation and has some parameters arbitrarily added but unexplained. According to the current models of big bang nucleosynthesis, the primordial composition of visible matter of the universe should be about 75% hydrogen and 25% helium-4 (in mass). Neutrons are made up of one up and two down quarks, while protons are made of two up and one down quark. Since the other common elementary particles (such as electrons, neutrinos, or weak bosons) are so light or so rare when compared to atomic nuclei, we can neglect their mass contribution to the observable universe's total mass. Therefore,