On unitarity of tree-level string amplitudes
Abstract Four-particle tree-level scattering amplitudes in string theory are magically consistent with unitarity, reflected in the non-trivial fact that beneath the critical dimension, the residues of the amplitudes on massive poles can be expanded in partial waves with all positive coefficients. Wh...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-02-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP02(2022)197 |
| _version_ | 1828751495593459712 |
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| author | Nima Arkani-Hamed Lorenz Eberhardt Yu-tin Huang Sebastian Mizera |
| author_facet | Nima Arkani-Hamed Lorenz Eberhardt Yu-tin Huang Sebastian Mizera |
| author_sort | Nima Arkani-Hamed |
| collection | DOAJ |
| description | Abstract Four-particle tree-level scattering amplitudes in string theory are magically consistent with unitarity, reflected in the non-trivial fact that beneath the critical dimension, the residues of the amplitudes on massive poles can be expanded in partial waves with all positive coefficients. While this follows (rather indirectly) from the no-ghost theorem, the simplicity of the statement and its fundamental importance for the physical consistency of string theory begs for a more direct and elementary understanding. In this note we take a step in this direction by presenting a new expression for the partial wave coefficients of string amplitudes, given by surprisingly simple double/triple contour integrals for open/closed strings. This representation allows us to directly prove unitarity of all superstring theories in D ≤ 6 spacetime dimensions, and can also be used to determine various asymptotics of the partial waves at large mass levels. |
| first_indexed | 2024-12-10T20:54:08Z |
| format | Article |
| id | doaj.art-a5ffff0ce6bf45498a29bd541a891e48 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-12-10T20:54:08Z |
| publishDate | 2022-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-a5ffff0ce6bf45498a29bd541a891e482022-12-22T01:34:00ZengSpringerOpenJournal of High Energy Physics1029-84792022-02-012022213510.1007/JHEP02(2022)197On unitarity of tree-level string amplitudesNima Arkani-Hamed0Lorenz Eberhardt1Yu-tin Huang2Sebastian Mizera3Institute for Advanced Study, Einstein DriveInstitute for Advanced Study, Einstein DriveDepartment of Physics and Center for Theoretical Physics, National Taiwan UniversityInstitute for Advanced Study, Einstein DriveAbstract Four-particle tree-level scattering amplitudes in string theory are magically consistent with unitarity, reflected in the non-trivial fact that beneath the critical dimension, the residues of the amplitudes on massive poles can be expanded in partial waves with all positive coefficients. While this follows (rather indirectly) from the no-ghost theorem, the simplicity of the statement and its fundamental importance for the physical consistency of string theory begs for a more direct and elementary understanding. In this note we take a step in this direction by presenting a new expression for the partial wave coefficients of string amplitudes, given by surprisingly simple double/triple contour integrals for open/closed strings. This representation allows us to directly prove unitarity of all superstring theories in D ≤ 6 spacetime dimensions, and can also be used to determine various asymptotics of the partial waves at large mass levels.https://doi.org/10.1007/JHEP02(2022)197Bosonic StringsScattering AmplitudesSuperstrings and Heterotic Strings |
| spellingShingle | Nima Arkani-Hamed Lorenz Eberhardt Yu-tin Huang Sebastian Mizera On unitarity of tree-level string amplitudes Journal of High Energy Physics Bosonic Strings Scattering Amplitudes Superstrings and Heterotic Strings |
| title | On unitarity of tree-level string amplitudes |
| title_full | On unitarity of tree-level string amplitudes |
| title_fullStr | On unitarity of tree-level string amplitudes |
| title_full_unstemmed | On unitarity of tree-level string amplitudes |
| title_short | On unitarity of tree-level string amplitudes |
| title_sort | on unitarity of tree level string amplitudes |
| topic | Bosonic Strings Scattering Amplitudes Superstrings and Heterotic Strings |
| url | https://doi.org/10.1007/JHEP02(2022)197 |
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