In this book we have systematically used the metric convention, ηµν = Diag[−1, +1, +1, +1], the “Pauli,” “East Coast,” or “mostly plus” metric. The other common convention, the “Bjorken and Drell,” “West Coast,” or “mostly minus” convention, takes ηµν = diag[+1, −1, −1, −1]. The “mostly minus” metric convention is currently in more common use in the field of phenomenology. The “mostly plus” convention predominates in the general relativity, string theory, supersymmetry, and formal field-theory communities.

To make this book more useful to its intended audience, who primarily use the opposite metric convention, we describe in this appendix the differences between these conventions, culminating in a “translation table” between the conventions, which should ease the difficulty in hopping between our conventions and the conventions appearing in most of the relevant literature. There are other conventions besides the metric which must be decided on, and these are not uniform in either community; since it would be too complicated to discuss every possible set of conventions, we will focus only on the most common coherent set of “mostly minus” conventions, taken to be those of Peskin and Schroeder, “An Introduction to Quantum Field Theory,” Westview, 1995.

Finally, we will end this section with an explanation of why we prefer the “mostly plus” metric. We postpone that discussion to the end because some physicists approach this issue with almost religious conviction, and it is important to us that you not slam this book shut before reading the rest of this appendix.