Helicity decoupling in the massless limit of massive tensor fields
Abstract
Massive and massless potentials play an essential role in the perturbative formulation of particle interactions. Many difficulties arise due to the indefinite metric in gauge theoretic approaches, or the increase with the spin of the UV dimension of massive potentials. All these problems can be evaded in one stroke: modify the potentials by suitable terms that leave unchanged the field strengths, but are not polynomial in the momenta. This feature implies a weaker localization property: the potentials are "stringlocalized". In this setting, several old issues can be solved directly in the physical Hilbert space of the respective particles: We can control the separation of helicities in the massless limit of higher spin fields and conversely we recover massive potentials with 2 s + 1 degrees of freedom by a smooth deformation of the massless potentials ("fattening"). We construct stressenergy tensors for massless fields of any helicity (thus evading the WeinbergWitten theorem). We arrive at a simple understanding of the van DamVeltmanZakharov discontinuity concerning, e.g., the distinction between a massless or a very light graviton. Finally, the use of stringlocalized fields opens new perspectives for interacting quantum field theories with, e.g., vector bosons or gravitons.
 Publication:

Nuclear Physics B
 Pub Date:
 November 2017
 DOI:
 10.1016/j.nuclphysb.2017.09.022
 arXiv:
 arXiv:1703.04407
 Bibcode:
 2017NuPhB.924..699M
 Keywords:

 High Energy Physics  Theory;
 Mathematical Physics
 EPrint:
 30 pages. v4: As published. v3: Introduction completely rewritten