Graviton loops and negativity

Abstract We revisit dispersive bounds on Wilson coefficients of scalar effective field theories (EFT) coupled to gravity in various spacetime dimensions, by computing the contributions from graviton loops to the corresponding sum rules at low energies. Fixed-momentum-transfer dispersion relations ar...

Full description

Saved in:
Bibliographic Details
Main Authors: Cyuan-Han Chang, Julio Parra-Martinez
Format: Article
Language:English
Published: SpringerOpen 2025-08-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP08(2025)175
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849226685852942336
author Cyuan-Han Chang
Julio Parra-Martinez
author_facet Cyuan-Han Chang
Julio Parra-Martinez
author_sort Cyuan-Han Chang
collection DOAJ
description Abstract We revisit dispersive bounds on Wilson coefficients of scalar effective field theories (EFT) coupled to gravity in various spacetime dimensions, by computing the contributions from graviton loops to the corresponding sum rules at low energies. Fixed-momentum-transfer dispersion relations are often ill-behaved due to forward singularities arising from loop-level graviton exchange, making naive positivity bounds derived from them unreliable. Instead, we perform a careful analysis using crossing-symmetric dispersion relations, and compute the one-loop corrections to the bounds on EFT coefficients. We find that including the graviton loops generically allows for negativity of Wilson coefficients by an amount suppressed by powers of Newton’s constant, G. The exception are the few couplings that dominate over (or are degenerate with) the graviton loops at low energies. In D = 4, we observe that assuming that the eikonal formula captures the correct forward behavior of the amplitude at all orders in G, and for energies of the order of the EFT cutoff, yields bounds free of logarithmic infrared divergences.
format Article
id doaj-art-e7cd71bbd7d54a1b9b3bc5816f084670
institution Kabale University
issn 1029-8479
language English
publishDate 2025-08-01
publisher SpringerOpen
record_format Article
series Journal of High Energy Physics
spelling doaj-art-e7cd71bbd7d54a1b9b3bc5816f0846702025-08-24T11:04:57ZengSpringerOpenJournal of High Energy Physics1029-84792025-08-012025815310.1007/JHEP08(2025)175Graviton loops and negativityCyuan-Han Chang0Julio Parra-Martinez1Walter Burke Institute for Theoretical Physics, CaltechInstitut des Hautes Études ScientifiquesAbstract We revisit dispersive bounds on Wilson coefficients of scalar effective field theories (EFT) coupled to gravity in various spacetime dimensions, by computing the contributions from graviton loops to the corresponding sum rules at low energies. Fixed-momentum-transfer dispersion relations are often ill-behaved due to forward singularities arising from loop-level graviton exchange, making naive positivity bounds derived from them unreliable. Instead, we perform a careful analysis using crossing-symmetric dispersion relations, and compute the one-loop corrections to the bounds on EFT coefficients. We find that including the graviton loops generically allows for negativity of Wilson coefficients by an amount suppressed by powers of Newton’s constant, G. The exception are the few couplings that dominate over (or are degenerate with) the graviton loops at low energies. In D = 4, we observe that assuming that the eikonal formula captures the correct forward behavior of the amplitude at all orders in G, and for energies of the order of the EFT cutoff, yields bounds free of logarithmic infrared divergences.https://doi.org/10.1007/JHEP08(2025)175Effective Field TheoriesScattering Amplitudes
spellingShingle Cyuan-Han Chang
Julio Parra-Martinez
Graviton loops and negativity
Journal of High Energy Physics
Effective Field Theories
Scattering Amplitudes
title Graviton loops and negativity
title_full Graviton loops and negativity
title_fullStr Graviton loops and negativity
title_full_unstemmed Graviton loops and negativity
title_short Graviton loops and negativity
title_sort graviton loops and negativity
topic Effective Field Theories
Scattering Amplitudes
url https://doi.org/10.1007/JHEP08(2025)175
work_keys_str_mv AT cyuanhanchang gravitonloopsandnegativity
AT julioparramartinez gravitonloopsandnegativity