FeynCraft: A Game of Feynman Diagrams

TL;DR

FeynCraft addresses the need for an accessible, interactive tool to learn Standard Model Feynman diagrams by allowing users to draw and validate diagrams in a browser. It uses a rule-based vertex validation scheme, deriving allowable vertices from quantum-number conservation and a mass-dimension rule: the sum of the field dimensions attached to a vertex must be $\le 4$, with fermions carrying dimension $\tfrac{3}{2}$ and bosons dimension $1$, and the Lagrangian density $\mathcal{L}$ having mass dimension $4$; this governs SM interactions rather than relying on a fixed list. The platform supports random and curated problem sets, overlays (color flow, shade flow, and interaction strength), and LaTeX export, making it valuable for undergraduates, lecturers, and researchers. It also details algorithms for problem/diagram generation, layout, and duplicate detection, and outlines future extensions to SMEFT and broader color-flow analyses.

Abstract

FeynCraft is a browser-based game that is designed to teach players the particle interactions of the Standard Model of particle physics, and how to link these interactions together to produce valid Feynman diagrams. It is primarily targeted at undergraduates and lecturers in introductory courses in particle physics, but we anticipate that it should also be useful for school pupils and teachers studying the basics of particle physics, and perhaps also current researchers. Users may draw particle lines and link them together to form vertices and complete diagrams, and FeynCraft determines invalid vertices using a sequence of simple rules, showing users which vertices are invalid and why. Diagrams may be drawn that involve both fundamental Standard Model particles and hadrons (where hadrons are represented by their constituent quark content). Users can also be presented with a process for which they must draw valid Feynman diagrams -- FeynCraft is able to generate such 'problems' at random, but there is also the facility to create, share, import and solve curated sets of problems. Alternatively, one is able to specify the process, and ask FeynCraft itself to generate the Feynman diagrams. Finally, we include several overlay options that give more information on a Feynman diagram (e.g. QCD colour flow, interaction strengths), and the option to export a drawn diagram as LaTeX code.

Figures (20)

• Figure 1: The main menu, the opening screen. From here users can play the tutorial, enter the sandbox, start solving problems, play the daily problem, and access palettes and credits.
• Figure 2: A labelled example of a FeynCraft diagram, showing neutron decay.
• Figure 3: The particle tabs, containing the particles to be drawn. The electron neutrino is selected, making it the currently drawn particle.
• Figure 4: Examples of validly drawn hadrons. All quarks are consecutive and separated from other quarks.
• Figure 5: An invalid diagram to demonstrate the controls to edit drawn diagrams.