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SUMMARY:Alexander Zhiboedov (CERN)
DTSTART:20210518T100000Z
DTEND:20210518T110000Z
DTSTAMP:20260513T222326Z
UID:CCTP_HEP/49
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CCTP_HEP/49/
 ">Probing gravitational EFTs with the four-graviton amplitude</a>\nby Alex
 ander Zhiboedov (CERN) as part of CCTP HEP Seminars\n\n\nAbstract\nWe disc
 uss constraints from perturbative unitarity and\ncrossing on the leading c
 ontributions of the higher-dimension operators\nto the four-graviton ampli
 tude in four spacetime dimensions. We focus on\nthe leading order effect d
 ue to exchange by massive degrees of freedom\nwhich makes the amplitudes o
 f interest IR finite. To test the\nconstraints we obtain nontrivial effect
 ive field theory data by\ncomputing and taking the large mass expansion of
  the one-loop\nminimally-coupled four-graviton amplitude with massive part
 icles up to\nspin 2 circulating in the loop. Remarkably\, the leading EFT 
 corrections\nto Einstein gravity of physical theories\, both string theory
  and QFT\ncoupled to gravity\, end up in minuscule islands which are much 
 smaller\nthan what is suggested by the generic bounds obtained from consis
 tency\nof the 2-2 graviton scattering amplitude. We discuss the underlying
 \nmechanism for this phenomenon.\n
LOCATION:https://researchseminars.org/talk/CCTP_HEP/49/
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