MPhys Physics with Theoretical Physics

The course provides theoretical concepts required to calculate a Feynman diagram for basic processes in particle physics.  

The course will teach techniques on how to calculate Feynman diagrams and how to translate this into experiments. The first weeks will concentrate on simple electromagnetic interactions and then show what is required to extend this to weak and strong interactions.  

The last third of the course will discuss particle interaction with matter and what the requirements are for building a particle physics detector, as well as giving an introduction to particle physics simulations.  

Pre-requisites:

Particle Physics PHYS30221 OR PHYS40222 Particle Physics (2025/26 only)

Anti-requisites:

PHYS40202 Advanced Quantum Mechanics (2025/26 only)

The unit aims to introduce relativistic quantum mechanics, providing students with understanding of the theoretical calculations that are then used to interpret experimental data. The unit also aims to provide students with a basic understanding of the detectors needed to perform experimental particle physics research.

On the successful completion of the course, students will be able to:  

ILO 1

Understand and apply theoretical basics of particle physics calculations and derive cross sections for basic scattering/annihilation processes

ILO 2

Explain the main concepts behind the electromagnetic interactions and identify changes required for strong interaction calculations and electron proton interactions.  

ILO 3

Value the requirement for electroweak unification and its consequences

ILO 4  

Identify the experimental challenges of modern particle physics experiments and define technical solutions

ILO 5

Explain qualitative and quantitative techniques applied to particle physics experiments

Week 1: Introduction and overview of the lecture course. Reminder of SM of particle physics, units, forces, Feynman diagrams. Reminder of QM needed for this course. Fermi’s golden rule. Phase space.

Week 2: Extension of Fermi’s Golden Rule and Phase Space to relativistic situations. How to calculate particle decay widths and 2->2 scattering.

Week 3: Relativistic QM: the Dirac equation, Dirac spinors, probability densities, antiparticles, spin and helicity states 

Week 4 and 5:  Interactions by particle exchange, Feynman rules for QED. e+e- annihilation as example to calculate Feynman diagram, including spin and chirality. Discussion of relevant experimental results.

Week 6: Extension to ep scattering and pp scattering. Requirements for QCD calculations.

Week 7: Extension to weak interactions Electroweak unification (W boson properties, decay, Z boson; how to get from weak interaction to electroweak unification, calculation of currents, how this results in Weinberg angle) 

Week 8:  basics of Higgs (1D example of symmetry breaking). Start of how to go from calculation to detection/experiment: overview and basics of Monte Carlo techniques 

Week 9: Particle interaction with matter. Bethe-Bloch formula, ionisation, multiple scattering, Molière radius, bremsstrahlung 

Week 10: History and basics of trackers and muon detectors. Basics of calorimeters. General performance numbers. 

Week 11: Trigger and data taking, data processing chain in modern experiments.

Week 12: Bringing everything together. Summary, Q&A 

A two-hour live in-person lecture will be delivered each week, including core material and example calculations. The recordings of these lectures will be on the course online page. The lectures are accompanied by summary notes. A Piazza discussion forum will also provided where students can ask questions with answers provided by other students and the unit lead. 

Modern Particle Physics, M. Thomson