Reddit reviews Introduction to Elementary Particles

This is a fantastic question. I'm really glad you asked it.

First, we need to correct your formula for energy. It's not, as we are so often told, "E=mc^2 ". That equation only works for things that are stationary. Things that can move obey the following, "E = gamma * mc^2 ". This raises the obvious question, what is gamma?

The term "gamma" is shorthand for (1-(v/c)^2 )^(-1/2) , where v is the velocity of whatever is moving, and c is the speed of light. So "gamma" is a funny term that starts at a value of 1 for things that are stationary, but gets bigger and bigger for things moving faster and faster. The closer something moves to the speed of light, the closer gamma gets to infinity!

So, now that we know about gamma, what energy do we expect photons with zero mass to have?

Well, "E = gamma * mc^2 ". m = 0, just like you said. But gamma = infinity. (!) What a clever trick the universe plays! It says that mass-less objects must have zero energy, except if they move at the speed of light! So, photons are, in some sense, a loophole in relativity. Their existence and their energy and momentum can be seen as a technicality that's only permitted if they move at light-speed.

Note: I lifted this interpretation from David J. Griffiths' excellent text "Introduction to Elementary Particles."

Author of two widely used undergratuate physics texts: one for Electricity and Magnetism and one for Quantum Mechanics. He also authored the somewhat-less-widely used (perhaps mainly because it's a specialist subject in most undergrad programs) Introduction to Elementary Particles.

Here's an elementary textbook.

I would spend some time learning math first.

Well if you are willing to delve into a textbook I would recommend Griffiths, it starts by introducing the history of particle physics, which is pretty cool, and the initial chapters aren't tooooo math heavy. You will probably need to have taken a course in quantum mechanics though.

For something less technical than a textbook, I can't give you a solid recommendation, but I've heard good things about The Infinity Puzzle.