Old and New No Go Theorems on Interacting Massless Particles in Flat Space

Abstract

We review model independent arguments showing that massless particles interacting with gravity in a Minkowski background space can have at most spin two. These arguments include a classic theorem due to Weinberg, as well as a more recent extension of the Weinberg-Witten theorem. A puzzle arising from an apparent counterexample to these theorems is examined and resolved.

References added. Based on a talk given at the conference QUARKS 2012, Yaroslavl, Russian Federation, June 4-10, 2012. To appear in the conference proceedings