Griffiths Introduction to Elementary Particles · Problem 7.22

Electrodynamics of Quarks and Hadrons — David J. Griffiths

Physics — QFT · completeness-relations-spinors

Problem

Using

u^{(1)}

u^{(2)}

(7.46) and

v^{(1)}

v^{(2)}

(7.50), prove the completeness relations (7.97). [Note that the matrix multiplication is ``backwards'':

u\bar{u}

is a

4\times 4

matrix, defined by

(u\bar{u})_{ij} = u_i\bar{u}_j