Conformal higher spin scattering amplitudes from twistor space

Timothy Adamo, Philipp Hähnel, Tristan McLoughlin

Research output: Contribution to journalArticlepeer-review


We use the formulation of conformal higher spin (CHS) theories in twistor space to study their tree-level scattering amplitudes, finding expressions for all three-point MHV mplitudes and all MHV amplitudes involving positive helicity conformal gravity particles and two negative helicity higher spins. This provides the on-shell analogue for the covariant coupling of CHS fields to a conformal gravity background. We discuss the restriction of the theory to a ghost-free unitary subsector, analogous to restricting conformal gravity to general relativity with a cosmological constant. We study the flat-space limit and show that the restricted amplitudes vanish, supporting the conjecture that in the unitary sector the S-matrix of CHS theories is trivial. However, by appropriately rescaling the amplitudes we find non-vanishing results which we compare with chiral flat-space higher spin theories.
Original languageEnglish
Article number21
Number of pages31
Journal Journal of High Energy Physics
Publication statusPublished - 4 Apr 2017


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