i figured out what g means in this diagram and found out that it represents a gluon. and then i looked into what gluons are. and now im interested in particle physics.

brings back memories of half life 1. also anti-matter is more simple than i thought
Its called a Feynman diagram
In this diagram you posted, an electron (e-) and positron (e+) collide to produce a Photon (y) that is represented by the blue sine wave and then eventually turns into a quark (q) and antiquark (q with the bar above) and the antiquark radiates a gluon which is represented by g
credit goes to science