2 Chiral and gauge symmetries

We begin with the discussion of chiral and gauge symmetries. These concepts

should all be familiar from the Michaelmas QFT course. But it is beneficial

to do a bit of review here. While doing so, we will set straight our sign and

notational conventions, and we will also highlight the important parts in the

theory.

As always, we will work in natural units

c

=

~

= 1, and the sign convention

is (+, −, −, −).