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 infinitedimensional KacMoody 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. Treelevel 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 bulkboundary 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 ChernSimons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of ChernSimons theory, AharonovBohm 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 »
 Authors:

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^{[2]}
 California Inst. of Technology (CalTech), Pasadena, CA (United States). Walter Burke Inst. for Theoretical Physics
 Univ. of Maryland, College Park, MD (United States). Dept. of Physics
 Publication Date:
 Grant/Contract Number:
 SC0010255; PHY1315155
 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 10298479
 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; AdSCFT 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 infinitedimensional KacMoody 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. Treelevel 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 bulkboundary 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 ChernSimons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of ChernSimons theory, AharonovBohm 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 KacMoody 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}
}