Worldline CPT and massless supermultiplets

Alex S. Arvanitakis, Luca Mezincescu, Paul K. Townsend

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The action for a massless particle in 4D Minkowski space-time has a worldline-time reversing symmetry corresponding to CPT invariance of the quantum theory. The analogous symmetry of the -extended superparticle is shown to be anomalous when is odd; in the supertwistor formalism this is because a CPT-violating worldline-Chern-Simons term is needed to preserve the chiral U(1) gauge invariance. This accords with the fact that no massless = 1 super-Poincaré irrep is CPT-self-conjugate. There is a CPT self-conjugate supermultiplet when is even, but it has 2+1 states when 1 2 is odd (e.g. the = 2 hypermultiplet) in contrast to just 2 when 1 2 is even (e.g. the = 4 Maxwell supermultiplet). This is shown to follow from a Kramers degeneracy of the superparticle state space when 1 2 is odd.

Original languageEnglish (US)
Article number1650152
JournalInternational Journal of Modern Physics A
Issue number27
StatePublished - Sep 30 2016


  • Superparticle
  • time reversal
  • twistors

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Astronomy and Astrophysics


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