## PHY 431: Particle Physics

3 credits | Prerequisites: PHY 222, 223, 301

### Course rationale

Human being has been inquisitive to know the fundamental building blocks of matter. Answer to this curious question has evolved with the accumulation of experimental data together with the better understanding from the theoretical side. Currently the most satisfactory explanation on the questions of particle physics is given by the Standard Model. In this course, the students will learn the basics of particle physics, and learn different Quantum Field Theoretical techniques to compute different quantities in particle physics.

### Course content

Introduction to Different Elementary Particles: natural units, photon, meson, antiparticles, neutrino, strange particles, eightfold way, quark model, four forces, Quantum Electrodynamics (QED), Quantum Chromodynamics (QCD), quarks, leptons, some experiments; Relativistic Kinematics: Lorentz transformation, four-vectors, energy and momentum, collisions, relativistic collisions, examples, Symmetry: symmetries, groups, and conservation laws, angular momentum, addition of angular momentum, isospin, flavor symmetry, discrete symmetry: parity, charge conjugation, time reversal, CPT theorem; Relativistic Wave Equations: the Klein-Gordon equation, fields and particles, Maxwell’s equation, the Dirac equation, relativistic normalization of states, spin and statistics; The Quark Atom: SU(3) group, isospin and strangeness, quark-antiquark system: meson, three-quark system: baryons, magnetic moments, heavy quarks, hadron masses, color factors; The Feynman Calculus: decay and scattering, decay rates, cross section, observables in particle experiments, master formulae for partial width and cross-sections, phase space, example of electron-positron annihilation, properties of massless spin ½ fermions, evaluation of matrix elements, calculation of cross-section; Deep Inelastic Scattering: the SLAC-MIT experiment, the parton model, crossing symmetry, cross section for electron-quark scattering, cross section for deep inelastic scattering; Quantum Chromodynamics (QCD): Lagrangian dynamics and gauge symmetry, Lie group, non-Abelian gauge symmetry, formulation of QCD, gluon; Chiral Symmetry: symmetries of QCD with zero quark masses, spontaneous symmetry breaking, Goldstone bosons, properties of pi mesons as Goldstone bosons; Introduction to Standard Model: development of V-A theory of weak interaction, some predictions, gauge theory with spontaneous symmetry breaking, W and Z boson, Higgs boson.

### Course objectives

- Understand the concept of elementary particle.
- Familiarize with different kinds of elementary particles.
- Understand basic tools from Quantum Field Theory to compute scattering cross section of different processes.
- Familiarize with the Feynman diagram.
- Familiarize with the Standard Model of particle physics.

### References

- Concepts of Elementary Particle Physics (3rd edition) by Michael E. Peskin
- Introduction to Elementary Particles (2nd edition) by David Griffiths
- Quarks and Leptons: An Introductory Course in Modern Particle Physics by Francis Halzen, and Alan D. Martin
- Introduction to High Energy Physics (4th edition) by Donald H. Perkins
- Modern Particle Physics by Mark Thomson