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Title: 4D scattering amplitudes and asymptotic symmetries from 2D CFT

We reformulate the scattering amplitudes of 4D at space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D at space. We derive these results by recasting 4D dynamics in terms of a convenient foliation of flat space into 3D Euclidean AdS and Lorentzian dS geometries. Tree-level scattering amplitudes take the form of Witten diagrams for a continuum of (A)dS modes, which are in turn equivalent to CFT correlators via the (A)dS/CFT dictionary. The Ward identities for the 2D conserved currents are dual to 4D soft theorems, while the bulk-boundary propagators of massless (A)dS modes are superpositions of the leading and subleading Weinberg soft factors of gauge theory and gravity. In general, the massless (A)dS modes are 3D Chern-Simons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of Chern-Simons theory, Aharonov-Bohm effects record the \tracks" of hard particles in the soft radiation, leading to a simple characterization of gauge and gravitational memories. Soft particle exchanges between hard processesmore » define the Kac-Moody level and Virasoro central charge, which are thereby related to the 4D gauge coupling and gravitational strength in units of an infrared cutoff. Lastly, we discuss a toy model for black hole horizons via a restriction to the Rindler region.« less
Authors:
 [1] ;  [2] ;  [2]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Walter Burke Inst. for Theoretical Physics
  2. Univ. of Maryland, College Park, MD (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
SC0010255; PHY-1315155
Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2017; Journal Issue: 1; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Research Org:
California Inst. of Technology (CalTech), Pasadena, CA (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Contributing Orgs:
Univ. of Maryland, College Park, MD (United States)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AdS-CFT Correspondence; Conformal Field Theory; Scattering Amplitudes
OSTI Identifier:
1360787

Cheung, Clifford, de la Fuente, Anton, and Sundrum, Raman. 4D scattering amplitudes and asymptotic symmetries from 2D CFT. United States: N. p., Web. doi:10.1007/JHEP01(2017)112.
Cheung, Clifford, de la Fuente, Anton, & Sundrum, Raman. 4D scattering amplitudes and asymptotic symmetries from 2D CFT. United States. doi:10.1007/JHEP01(2017)112.
Cheung, Clifford, de la Fuente, Anton, and Sundrum, Raman. 2017. "4D scattering amplitudes and asymptotic symmetries from 2D CFT". United States. doi:10.1007/JHEP01(2017)112. https://www.osti.gov/servlets/purl/1360787.
@article{osti_1360787,
title = {4D scattering amplitudes and asymptotic symmetries from 2D CFT},
author = {Cheung, Clifford and de la Fuente, Anton and Sundrum, Raman},
abstractNote = {We reformulate the scattering amplitudes of 4D at space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D at space. We derive these results by recasting 4D dynamics in terms of a convenient foliation of flat space into 3D Euclidean AdS and Lorentzian dS geometries. Tree-level scattering amplitudes take the form of Witten diagrams for a continuum of (A)dS modes, which are in turn equivalent to CFT correlators via the (A)dS/CFT dictionary. The Ward identities for the 2D conserved currents are dual to 4D soft theorems, while the bulk-boundary propagators of massless (A)dS modes are superpositions of the leading and subleading Weinberg soft factors of gauge theory and gravity. In general, the massless (A)dS modes are 3D Chern-Simons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of Chern-Simons theory, Aharonov-Bohm effects record the \tracks" of hard particles in the soft radiation, leading to a simple characterization of gauge and gravitational memories. Soft particle exchanges between hard processes define the Kac-Moody level and Virasoro central charge, which are thereby related to the 4D gauge coupling and gravitational strength in units of an infrared cutoff. Lastly, we discuss a toy model for black hole horizons via a restriction to the Rindler region.},
doi = {10.1007/JHEP01(2017)112},
journal = {Journal of High Energy Physics (Online)},
number = 1,
volume = 2017,
place = {United States},
year = {2017},
month = {1}
}