Do gluons travel backwards in time? And what is spin?

StevenBensics

New member
Two Questions. I've been studying some quantum mechanics online.

Having studied chemistry, I understand "charge," for protons, neutrons, electrons and ions and such, but what exactly is "spin" for sub-subatomic particles (quarks and such)? How can they have values like +1/2 and -1/2 and such? What are they a measure of?

Also, do gluons travel backwards in time? I found something called a Feynman Diagram. It's a Cartesian plot with spatial position in the y-axis and time in the x-axis.

Apparently, when a positron and electron collide, they annihilate and form a single gamma ray, which then splits off into a quark and antiquark.

But the antiquark shows a coiled path of a gluon splitting off it with loops that go backward in time. So I'm wondering, do gluons travel backwards in time? How is that possible?
 
Top