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SUMMARY:One-Loop Renormalization and the S-matrix - David Mcgady (Princeto
 n University)
DTSTART:20120531T120000Z
DTEND:20120531T130000Z
UID:TALK38433@talks.cam.ac.uk
CONTACT:Sungjay Lee
DESCRIPTION:In this talk\, I will discuss the proportionality between tree
  amplitudes and the ultraviolet divergences in their one-loop corrections 
 in Yang-Mills and (N < 4) Super Yang-Mills theories in four-dimensions. Fr
 om the point of view of local perturbative quantum field theory\, i.e. Fey
 nman diagrams\, this proportionality is straightforward: ultraviolet diver
 gences at loop-level are absorbed into coefficients of local operators/int
 eraction vertices in the original tree-amplitude. Ultraviolet divergences 
 in loop amplitudes are also calculable through on-shell methods. These met
 hods ensure manifest gauge-invariance\, even at loop-level (no ghosts)\, a
 t the expense of manifest locality. From an on-shell perspective\, the pro
 portionality between the ultraviolet divergences the tree amplitudes is th
 us not guaranteed. I describe systematic structures which ensure proportio
 nality\, and their possible connections to other recent developments in th
 e field.
LOCATION:Potter Room (first floor\, Pav. B)
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