# Feynman diagram neutron arrow

1. Apr 6, 2015

### thegirl

The arrows in a Feynmann diagram represent electric current. right? If this is the case then why do neutrons and neutrinos have arrows. How do they have an electric current?

2. Apr 6, 2015

### thegirl

sorry for the spelling mistakes

3. Apr 6, 2015

### Staff: Mentor

No they do not. They follow matter fermions (in arrow direction) or their antiparticles (against arrow direction).
The electric charge is not relevant, and an electric current is something completely different.

4. Apr 6, 2015

### thegirl

what do you mean when you say follow matter fermions, how the the arrows follow matter fermions? do you mean the direction? So the arrows do represent direction except for an antiparticle where the arrow is in the opposite to the direction?

Sorry, I'm a little lost as I was told they represented the direction the the electric current is in which is why the arrows for a particle and antiparticle where in different directions.

5. Apr 6, 2015

### thegirl

I just read up about it, and understand that they represent particle flow. So no one else has heard of the arrows representing the direction of the electric current?

6. Apr 6, 2015

### Staff: Mentor

It is completely wrong for Feynman diagrams.

You can use arrows in circuit diagrams (with resistors and so on), but that has nothing to do with Feynman diagrams.

7. Apr 6, 2015

### Avodyne

Arrows represent the flow of a conserved charge: it could be electric charge, baryon number, or lepton number, to give 3 examples.

8. Apr 7, 2015

### Staff: Mentor

Baryon number and lepton number: fine, I can see that.
Electric charge... well, consider the process "up -> down + W+" - the arrows have no relation to the flow of electric charge.