In 1962 Gell-Mann and Neeman (both working independently) observed that elementary particles called hadrons can be grouped in bigger units - so called supermultiplets organised into singlets, octets and decuplets. At its initial stages such a classification resembled first attempts at classifying elements into periodic table by Mendeleev and it allowed to predict new particles. Although at the time the classification was proposed its importance was not fully recognised, it was understood that, mathematically, it relies on non-alterable representations of the group SU(3), which in turn allows to predict octets and decuplets. Gell-mann called his theory the Eightfold Way.
A technique for making and utilising three-dimensional pictures using beams of light of amplitude and (coherent) radiation phase reflected from the original object, i.e. holography was practically implemented after the invention of laser by E.N. Leith and J. Upatnieks in 1962 and W. Stroke in 1963. Utilising the property of interference for recording information was theoretically analysed by Polish physicist W. Wolfke in 1920.
Val Fitch and James Cronin, the experimenters from Princeton doing research into neutral kaons (subatomic particles discovered during experiments carried out between 1956 - 1958 in Brookhaven) obtained data proving that C-P (combined charge and parity) symmetry in the decay of K-mesons is in fact violated.
In mid-1960-ties physicists became aware of the fact that the theory of matter built of protons, neutrons and electrons does not explain the existence of numerous newly discovered particles. In 1964 Murray Gell-Mann and George Zweig developed the theory of quarks. According to this theory baryons and mesons (which are hadrons, i.e. particles which interact strongly with other particles) consist of three quarks or anti-quarks called respectively 'up', 'down' and 'strange' one.
In spring 1964 Penzias and Wilson recorded by serendipity a hissing radio noise, which is now considered the echo of a sudden gigantic explosion of the Universe, called the Big Bang. The noise is the remnant of the early stages of the evolution of the Universe. It is referred to as relic radiation or cosmic microwave background radiation (CMB). The existence of CMB was predicted by G. Gamow in 1948.
Sheldon Glashow, Abdus Salam and Steven Weinberg proposed independently the theory describing electromagnetic forces in combination with weak interactions. The unified theory linked radioactive phenomena and thermonuclear reactions which occur in the stars with better researched effects of electricity and magnetism. Glashow, Salama and Weinberg's electroweak interaction theory predicted the existence of the gauge bosons; neutral (called ZO) and charged (called respectively W+ and W-). The discovery of ZO intermediate particles was indicative of the existence of natural neutral weak interactions, which had never been observed before.