# PX395 The Standard Model

## Lecturer: Steve Boyd

## Weighting: 7.5 CATS

The Standard Model (SM) describes elementary particles (the quarks, leptons, and bosons) using gauge theories. Although a full quantitative description of the SM requires the machinery of quantum field theory and is not easily accessible, it is quite possible to develop a good qualitative understanding of what is meant by a gauge theory and how this constrains the predictions of the model. A lot follows from symmetry. We will look at Noether's theorem (for any continuous symmetry property there is a conserved quantity, eg conservation of charge and invariance under gauge transformations are the same thing), flavour symmetry, parity (P) and others. The module shows how these aspects of the model are tested against experiment. It also looks at the reasons for quark confinement and the concept of a momentum-transfer dependent coupling, the Higgs mechanism, quark mixing and questions about unification.

**Aims:**

To describe the standard model of particle physics

**Objectives:**

At the end of the module, you should

- Understand qualitatively how elementary particles and their interactions are described in the standard model
- Be able to demonstrate quantitatively important aspects of the model and quote experimental evidence that supports it
- Appreciate the limitations of the established theory

**Syllabus:**

**Introduction, Preliminaries and Revision**

Particle content, roles of fermions and bosons, anti-particles and virtual boson propagators. The fundamental role of symmetry. Flavour symmetry, parity (P), helicity, charge conjugation (C), CP and CPT

**Aspects of the Strong Interaction**

Quark model, evidence for quarks/colour. Running coupling, understanding of confinement, explanation of the OZI Rule, fragmentation/jet production.

**Aspects of Weak Interactions**

Charged and neutral-current interactions; Cabibbo/GIM theory, quark mixing, CKM matrix; The phenomena of mixing and CP-violation.

**The Structure of the Standard Model**

The Feynman Rules for spinless particle scattering and the calculation of cross-sections/decay rates based on Fermi’s Golden Rule. Introduction to the fundamental interactions as local gauge theories of the interactions (QED, QCD and Electroweak).

**Commitment:** 15 Lectures

**Assessment:** 1.5 hour examination

This module has a home page.

**Recommended Texts:**

Introduction to Elementary Particles, David Griffiths, Wiley

Modern Elementary Particle Physics, Gordon Kane, Addison Wesley

Particle Physics, B.R. Martin and G. Shaw, Wiley

Introduction to High Energy Physics, Donald Perkins, Addison Wesley

**Leads to:** Fourth Year modules on Particles.