Symmetries of the QCD

An important feature of the QCD is the conspicuous amount of symmetries of its lagrangian. First and foremost, its lagrangian is invariant under local gauge transformations, i.e. one can redefine the quark fields indipendently at every point in the space-time, without changing the physical content of the theory. This determines a number of implications in … Continue reading Symmetries of the QCD

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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