**History of Science**

Environmental & Science Education

Edward Hessler

When you hear the phrase "the standard model of particle physics" what comes to mind?

By AffectioNet (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons |

Did you include equations or a big, a really big equation? I thought about equations but not the gargantuan equation of the standard model. I'd never even thought to look at it.

Thomas D. Gutierriz of California Polytechnic University has transcribed the Standard Model Lagrangian (more about this below) for the web. It is found in Symmetry (July 28, 2016). He calls attention to a sign error he made while writing it, i.e., he knows it is there (somewhere). I'll leave the finding of this error to others since I don't understand a single thing in this handsome equation.

The article's author, Rashmi Shivni writes that "the Lagrangian is a fancy way of writing an equation to determine the state of a changing system and explain the maximum possible energy the system can maintain." There are other ways to express these equations.

Shivni's essay first shows the entire equation and then separates it into five sections. For each of the sections, Shivni briefly describes what is represented by the symbols. A prediction of the standard model is that neutrinos are mass less and Shivni draws our attention to this. Neutrino oscillations (1998) defied this prediction.

For several Thanksgivings, CalTech's Sean Carroll has given thanks for an equation. On November 23, 2006 he gave thanks for the Lagrangian of the Standard Model of Particle Physics.

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