# What is this equation?

## Recommended Posts

Hi, I had been looking all over the internet for this equation that describes everything except gravity. I finally found it but it is on a shirt! :S

The name of the equation

What it means

And it put in layman terms

Any other information you have on it would be great.

I'm new to it and it interests me so i would really like to know more about it. Thank you.

Edit: Forgot the bloody link! Stupid me. XD

http://www.zazzle.co...614641326468730

Edit 2: I think it is called the Higgs Field. But I'm not sure.

Edited by morgsboi

##### Share on other sites

Yes, it looks like the Lagrangian for the standard model.

##### Share on other sites

Thanks to you both, can anyone explain it?

##### Share on other sites

Thanks to you both, can anyone explain it?

What do you mean?

##### Share on other sites

This equation is the Standard Model of particle physics. It describes what the world is and what holds it together. In other words, it explains the fundamental particles in the universe and the forces with which they interact, except for general relativity.
##### Share on other sites

What do you mean?

So, what do the symbols mean so I can actually understand the whole equation. I know what the particles are. Anyway, I'm just doing something new really.

##### Share on other sites

So, what do the symbols mean so I can actually understand the whole equation. I know what the particles are. Anyway, I'm just doing something new really.

If you don't understand the math behind it already, there's not a whole lot of explaining that can be done short of teaching you loads of math.

##### Share on other sites

If you don't understand the math behind it already, there's not a whole lot of explaining that can be done short of teaching you loads of math.

I understand the math, I just don't understand all the math symbols.

##### Share on other sites

• 2 weeks later...

Knowing the math includes knowing the symbols and operators- http://physics.info/symbols/.

Have fun learning the math.

##### Share on other sites

Thanks to you both, can anyone explain it?

Basically there's this thing called "action" (denoted with the symbol S) and things always follow a path that extremizes the action (makes it as small or large as possible*). The action is the integral of the Lagrangian density over spacetime:

$S=\int \mathcal{L}d^4x$

So to find the path on which things move, you just extremize the action:

$\delta S=0$

*Technically it doesn't need to be a minimum or maximum - it can also be a "saddle point," but this is just a technicality.

Edited by elfmotat

## Create an account

Register a new account