Abstract

Higher-spin (HS) gauge theories involve a massless particle of spin two, that is a graviton, together with (typically infinitely many) gauge fields of spin greater than two. An important motivation for their study originates from the long-standing difficulties encountered in the quantisation of gravity, which impel to explore extensions thereof that may have a better UV behaviour. Including fields of spin greater than two is mainly suggested by two observations: the constraints brought by a larger gauge symmetry may remove some UV divergences as supersymmetry does, and string theory does involve fields of arbitrary spin. HS gauge theories are indeed models of intermediate complexity with respect to these examples, and aspire to improve the UV behaviour of supergravity models without resorting to fully-fledged string theory and its plethora of additional particles.