The Higgs mechanism

The simplest way to implement the SSB in the electroweak theory is achieved by adding the Higgs field, a complex scalar isospin doublet with four degrees of freedom, Without affecting the gauge invariance, it is possible to add to the Lagrangian of the electroweak interaction (*) the term which indicates the SSB, with  and in the potential explicited … Continue reading The Higgs mechanism


Fields with physical significance are those that verify the Euler--Lagrange equations, or that satisfy the Hamilton's principle. For such systems, a general and systematic procedure is available to establish conservation theorems and constants of motion, as a consequence of invariance properties. Thus, conservation laws and selection rules observed in Nature may be imposed as symmetries of … Continue reading Symmetries

Electromagnetic interactions

The electromagnetic interaction is described by a gauge theory headed by the symmetry group whose density of the Lagrangian can be written as: where is the electromagnetic field tensor and is the gauge covariant derivative, with indicating the covariant four-potential of the electromagnetic field, generated by the charge ; is the external field due to … Continue reading Electromagnetic interactions