tony876

Hi I am supposed to write a 5000 word essay on a Weinberg-Witten Theorem which forbids the existence of massless particles with helicity j > 1 in any theory with a Lorentz-covariant energy-momentum tensor and how both graviton and gluon evade the assumptions of this proof due to gauge symmetry. I was wondering whether anybody could point out some references which might be useful. Thanks in advance