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DTSTART:19700329T010000
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CATEGORIES:Quantum Fields and Strings Seminars
SUMMARY:One-Loop Renormalization and the S-matrix - David 
 Mcgady (Princeton University)
DTSTART;TZID=Europe/London:20120531T130000
DTEND;TZID=Europe/London:20120531T140000
UID:TALK38433AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/38433
DESCRIPTION:In this talk\, I will discuss the proportionality 
 between tree amplitudes and the ultraviolet diverg
 ences in their one-loop corrections in Yang-Mills 
 and (N < 4) Super Yang-Mills theories in four-dime
 nsions. From the point of view of local perturbati
 ve quantum field theory\, i.e. Feynman diagrams\, 
 this proportionality is straightforward: ultraviol
 et divergences at loop-level are absorbed into coe
 fficients of local operators/interaction vertices 
 in the original tree-amplitude. Ultraviolet diverg
 ences in loop amplitudes are also calculable throu
 gh on-shell methods. These methods ensure manifest
  gauge-invariance\, even at loop-level (no ghosts)
 \, at the expense of manifest locality. From an on
 -shell perspective\, the proportionality between t
 he ultraviolet divergences the tree amplitudes is 
 thus not guaranteed. I describe systematic structu
 res which ensure proportionality\, and their possi
 ble connections to other recent developments in th
 e field.
LOCATION:Potter Room (first floor\, Pav. B)
CONTACT:Sungjay Lee
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