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SUMMARY:Poincaré symmetry shapes the massive 3-point amplitude
DTSTART:20161130T140000
DTEND:20161130T150000
DTSTAMP:20260916T050617Z
UID:1db90730ff984ecf58dc4b3b5c7ee6730b379d33939359b49568dc62
CATEGORIES:Conferences - Seminars
DESCRIPTION:Andrea Marzolla\nPoincaré invariance imposes strong non-pertu
 rbative constraints on the dependence of scattering amplitudes on the kine
 matical variables. For massless external states\, Benincasa and Cachazo ha
 ve shown that the 3-point amplitude is fully determined up to a constant (
 the coupling). We extend their approach\, based on the spinor-helicity for
 malism\, to time-like momenta\, and we find that\, even when massive exter
 nal states are involved\, the functional form of the 3-point amplitude is 
 fully determined\, up to (several) constants.\nIn this talk I review the d
 erivation in the massless case\, enlightening the role of the little group
  covariance of the amplitude in constraining its functional form\, and the
  particularly simple form that these constraints get in the spinor languag
 e. Then I will show how to extend this procedure to the massive case\, der
 iving the constraining equations for the massive little group\, and eventu
 ally showing the expressions for 3-point amplitudes involving one\, two\, 
 or three massive particles.
LOCATION:BSP 727 https://plan.epfl.ch/?room==BSP%20727
STATUS:CONFIRMED
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