IB Physics: Feynman Diagrams

Exchange particles are the Gauge Force particles like the photon, W, and Z boson particles. Their exchange between their respective Leptons or Quarks as these interactions occur. Write "OK" to continue.

Virtual particles are difficult to understand (meaning I don't really understand them). The best explanation I've come across is to not think of them as particles but as disturbances in the field. Of course the field is really particles, or virtual particles, sheesh! Don't worry about what virtual particles are because I've never seen a question on them. You will need to interpret or build Feynman Diagrams. We're not PhD students so don't worry about understanding everything perfectly. Just do what you don't really understand by rote. Type "OK" to continue.

One of the things you learn in HL is that photons, even though they have no mass, impart momentum on particles. So one electron emitting a photon will be pushed in the opposite direction from the emission, while absorbing it will push it in the direction the photon was moving. This causes the repulsion we see in like charges. Type "OK" to continue.

Notice the arrow head on the arrow isn't at the end like normal. This is because these are not vectors. This is just an indication which direction in time and space this is happening. Do NOT think of these are vectors. Type "OK" to continue.

Note that the time and space are not really axes, they're general measurements. Time is really just before, during, and after.  It turns out that anti-particles actually exist in reverse time. This is one of those things to just accept. It's not explained, nor are you expected to understand it, just know it. Type "kO" to continue.

Notice, in this case he didn't say it was a virtual particle. This is one of the Gauge Force particles (W) represented by the dashed line. Type "OK" to continue.

This stuff gets crazy so just follow the rules and worry about what it all really means when you get your Particle Physics PhD. Type "OK" to continue.

This is a Proton decaying into a Neutron through Positron decay. Since you can't draw your diagram here, describe your diagram to continue.