AstroII(2022)Lecture 3: Electro-weak Symmetry Breaking (Prof. Binil Aryal, IoST, TU / 8 April 2022)

This is my third lecture on 'standard big bang model' in which I attempted to explain a beautiful story of the birth of first proton in the Universe. In this lecture, I tried to explain expressions for Lagrangian before and after spontaneous symmetry breaking. The fascinating concept of 'baryogenesis process' has been described. In the electroweak theory, electromagnetism and the weak interactions—so different in range and apparent strength—are ascribed to a common gauge symmetry. We say that the electroweak gauge symmetry is broken, by dynamics or circumstances, to the gauge symmetry of electromagnetism. The Higgs boson is the particle associated with the mechanism that allows the symmetry of the electroweak force to be broken, or hidden, at low energies and that gives the W and Z particles, the carriers of the weak force, their mass.