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RESEARCH PRODUCT

The Standard Model

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Publisher Summary The weak interactions of the elementary particles are discovered in β-decay processes. They are described by an effective Lagrangian of current × current type in which the weak currents are coherent superpositions of charged vector and axial-vector currents, accounting for the violation of parity. The Fermi theory of the weak interactions can only be interpreted as an effective low-energy theory that cannot be extended to arbitrarily high energies. Applying this theory to the scattering process at high energies, the scattering amplitude rises indefinitely with the square of the energy. The structure of the electroweak system that has emerged from the requirement of asymptotic unitarity can theoretically be formulated as a gauge field theory. The fundamental forces of the standard model—the electromagnetic, the weak, and the strong forces—are mediated by gauge fields. This concept could consistently be extended to massive gauge fields by introducing the Higgs mechanism, which generates masses without destroying the underlying gauge symmetries of the theory.