Quantum Chromodynamics

The nucleus of an atom is made of protons and neutrons. Protons and neutrons are themselves divisible and composed of elementary particle quarks. Quarks can have charge \(\frac {2}{3} e\) as in quarks \(u, c, t\) or charge \(-\frac {1}{3} e\) as in quarks \(d, s, b\) . As \(electron, neutrino\) forms a doublet \(\left ( \begin {array}{c} e \\ \nu \end {array} \right ) \) which interacts through weak force we have the doublets \(\left ( \begin {array}{c} u \\ d \end {array} \right ) \) , \(\left ( \begin {array}{c} c \\ s \end {array} \right ) \) and \(\left ( \begin {array}{c} t \\ b \end {array} \right ) \) forms a doublet which interacts through weak force.