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SUMMARY:The polarized scattering equations and super-amplitudes for gauge\
 , gravity and brane theories in 6\, 10 and 11d - Lionel Mason (Oxford)
DTSTART:20200227T130000Z
DTEND:20200227T140000Z
UID:TALK137167@talks.cam.ac.uk
CONTACT:Dr. Carl Turner
DESCRIPTION:Six-dimensional theories provide a unification of four-dimensi
 onal theories via dimensional reduction and access to some of the novel fe
 atures arising from M-theory.  Ambitwistor strings directly generate S-mat
 rices for massless theories in terms of formulae that localize on the solu
 tions to the scattering equations\; algebraic equations that determine n p
 oints on the Riemann sphere from n massless momenta.  These are sufficient
  to provide compact formulae for tree-level S-matrices for bosonic theorie
 s. This talk introduces their extension to the polarized scattering equati
 ons that arise from twistorial versions of ambitwistor-strings.  These lea
 d to simple explicit formulae for superamplitudes in  6d for gauge\, gravi
 ty and brane theories and the framework extends to 10 and 11 dimensions.  
 These satisfy a double copy principle that leads to analogous formulae for
  theories containing gerbes\, but their physical interpretation remaions c
 ontroversial. This is based on joint work with Yvonne Geyer\, arxiv:1812.0
 5548 and 1901.00134 and with Giulia Albonico also 2001.05928.
LOCATION:Potter Room (first floor\, Pav. B)
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