Quarks are elementary, subatomic particles that form the framework for our understanding of the fundamental constituents and forces of the Standard Model of particle physics.
In 1964, physicists Murray Gell-Mann and George Zweig were working independently on a theory for strong interaction symmetry in particle physics. But it wouldn’t be until 1968 that the confirmation of quarks came through a series of experiments conducted by Richard Feynman and others. Deep inelastic scattering experiments provided indirect evidence supporting the existence of quarks. In 1974, experiments at the Stanford Linear Accelerator Center (SLAC) provided conclusive evidence for the existence of quarks. The experiments involved scattering high-energy electrons off protons, and the results were consistent with the presence of point-like constituents within the protons, confirming the quark model.