Sit down for coffee with the Standard Model

The Standard Model Lagrangian equation, seen on t-shirts and mugs from CERN, is explained line-by-line in a new paper aimed at teachers


Sit down for coffee with the Standard Model

The Standard Model Lagrangian on a mug available in the CERN shop (Image: CERN)

A new, open-access paper, published in Physics Education, helps teachers to explain the Standard Model and the equation used to describe it.

The Standard Model of particle physics is one of the most successful theories about how our Universe works, and describes the fundamental interactions between elementary particles. It is encoded in a compact description, the so-called 'Lagrangian', which even fits on t-shirts and coffee mugs.

This particular formula draws a lot of attention and everyone who visits CERN will come across it at some point. For example, the CERN gift shop sells t-shirts and coffee mugs featuring this four-line version of the Lagrangian. This can be especially challenging for physics teachers, who might then be asked by interested students to explain the meaning and the physics behind the Lagrangian.

But now, no one needs to stress about how to explain the equation, as this new paper provides a qualitative explanation of the terms of the Lagrangian and their interpretation, based on associated Feynman diagrams

Hopefully, this paper will support high school teachers in their challenging endeavour of introducing particle physics in the classroom, and guide interested students towards the fascinating world of quantum field theory.


Find out more:

Woithe, J., Wiener, G. J., & Van der Veken, F. F. (2017). Let’s have a coffee with the Standard Model of particle physics!. Physics Education, 52(3), 034001.