Conceptual Foundations of Modern Particle Physics

For scientific, technological and organizational reasons, the end of World War II (in 1945) saw a rapid accceleration in the tempo of discovery and understanding in nuclear physics, cosmic rays and quantum field theory, which together triggered the birth of modern particle physics. The first 15 years (1945-60) following the war's end - the "Startup Period" in modern particle physics - witnessed a series of major experimental and theoretical developments that began to define the conceptual contours (non-Abelian internal symmetries, Yang-Mills fields, renormalization group, chirality invariance, baryon-lepton symmetry in weak interactions, spontaneous symmetry breaking) of the quantum field theory of three of the basic interactions in nature (electromagnetic, strong and weak). But it took another 15 years (1960-75) - the "Heroic Period" in modern particle physics - to unravel the physical content and complete the mathematical formulation of the standard gauge theory of the strong and electroweak interactions among the three generations of quarks and leptons. The impressive accomplishments during the "Heroic Period" were followed by what is called the "period of consolidation and speculation (1975-1990)", which includes the experimental consolidation of the standard model (SM) through precision tests, theoretical consolidation of SM through the search for more rigorous mathematical solutions to the Yang-Mills-Higgs equations, and speculative theoretical excursions "beyond SM". Within this historical-conceptual framework, the author - himself a practicing particle theorist for the past 50 years - attempts to trace the highlights in the conceputal evolution of modern particle physics from its early beginnings until the present time. Apart from the first chapter - which sketches a broad overview of the entire field - the remaining nine chapters of the book offer detailed discussions of the major concepts and principles that prevailed and were given wide currency during each of the 15-year periods that comprise the history of modern particle physics.