PH-703 Quantum Field Theory II
- Non-abelian gauge theories: Yang-Mills Lagrangian, local and global gauge transformation. Multiple vacua.
- Brief review of group theory, quantization of non-abelian gauge theories, ghost field (BRS transformations).
- Unitarity: ghost field and unitarity, optical theorem and Cutkosky rules, examples: e + e → hadrons (evidence of color).
- Radiative corrections in QCD: one loop divergences (gauge boson self-energy, fermion self-energy), fermion gluon vertices, beta function and asymptotic freedom.
- Callan-Symanzik equation: renormalization scale, methods of characteristics, examples in φ4 theory and QCD.
- Weak interactions and Fermi theory: spontaneous symmetry breaking, massive gauge bosons (Higgs mechanism), Goldstone theorem with application to pi-sigma lagrangian, Goldstone bosons.
- Electroweak unification: Gauge theory with spontaneous symmetry breaking, neutral and charged currents, radiative corrections from fermionic loops, Higgs couplings, Higgs contribution to vector boson self energy, calculation: top quark decay into (i) W + b (ii) φ+ b, Higgs decay into: (i) W+W (ii) φ + W (iii) φ + φ, Yang Mills character of W-bosons (triple tri-linear coupling), triangle anomaly.
- Multiple vacua in QCD and the strong CP problem.
Recommended texts:
- An Introduction to Quantum Field Theory, M.E.Peskin and D.V.Schroeder, 1995.
- Quantum Field Theory, F. Mandl and G. Shaw, (Wiley, 1993).
- Quantum Field Theory in a Nutshell, A. Zee, (Princeton University Press, 2003).
- Quantum Field Theory, M. Srednicki , (Cambridge University Press, 2007)