Unitarity of time-like noncommutative gauge theories: the violation of Ward identities in time-ordered perturbation theory
We study Ward identities for simple processes with external gauge bosons in the time-ordered perturbation theory approach to time-like noncommutative gauge theories. We demonstrate that these Ward identities cannot be satisfied when all orders in the noncommutativity parameters θi0 are taken into account. We conclude that in time-ordered perturbation theory one cannot solve the unitarity problem of time-like noncommutative quantum field theories.
Nuclear Physics B
- Pub Date:
- January 2004
- High Energy Physics - Theory
- 16 pages LaTeX (feynmp.sty, elsart.cls and thophys.sty included). Clarified the comments on Seiberg-Witten Maps, updated references. This version has been accepted for publication in Nuclear Physics B