Causality constraints on nonlinear supersymmetry
Abstract It is well-known that gravitino propagation in standard supergravities is free of any causality problems. However, two issues related to gravitino propagation were recently uncovered in specific supergravities with nonlinear supersymmetry. One of them concerns potential acausality/superlumi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-11-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP11(2022)113 |
| _version_ | 1797865745003053056 |
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| author | Quentin Bonnefoy Gabriele Casagrande Emilian Dudas |
| author_facet | Quentin Bonnefoy Gabriele Casagrande Emilian Dudas |
| author_sort | Quentin Bonnefoy |
| collection | DOAJ |
| description | Abstract It is well-known that gravitino propagation in standard supergravities is free of any causality problems. However, two issues related to gravitino propagation were recently uncovered in specific supergravities with nonlinear supersymmetry. One of them concerns potential acausality/superluminality, whereas the second one arises from the vanishing of the sound speed at specific points during inflation. The former is famously related to positivity constraints on specific EFT operators, derived from dispersion relations on the energy-growing part of scattering amplitudes, and indeed we show that subluminality constraints for the gravitino are related via the equivalence theorem to positivity bounds in low-energy goldstino actions. However, the former are stronger, in the sense that they apply to functions of the scalar fields not only in the ground state, but for any field values such as those scanned by time-dependent solutions, unlike bounds derived from 2 → 2 scattering amplitudes in the vacuum. We also argue that nontrivial causality constraints arise only in the case where nonlinear supersymmetry in the matter sector is encoded into superfield constraints which do not seem to arise from microscopic two-derivative lagrangians, in particular for the orthogonal constraint used to build minimal models of inflation in supergravity. This allows us to propose simple alternatives which maintain the minimality of the spectra and are causal in all points of the theory parameter space. We also discuss minimal supergravity models of inflation along these lines. |
| first_indexed | 2024-04-09T23:13:07Z |
| format | Article |
| id | doaj.art-73fdf6e3b3e7427cae94ddf3813d1ac7 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-04-09T23:13:07Z |
| publishDate | 2022-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-73fdf6e3b3e7427cae94ddf3813d1ac72023-03-22T10:14:57ZengSpringerOpenJournal of High Energy Physics1029-84792022-11-0120221113810.1007/JHEP11(2022)113Causality constraints on nonlinear supersymmetryQuentin Bonnefoy0Gabriele Casagrande1Emilian Dudas2Deutsches Elektronen-Synchrotron DESYCentre de Physique Théorique, École Polytechnique, CNRS and IP ParisCentre de Physique Théorique, École Polytechnique, CNRS and IP ParisAbstract It is well-known that gravitino propagation in standard supergravities is free of any causality problems. However, two issues related to gravitino propagation were recently uncovered in specific supergravities with nonlinear supersymmetry. One of them concerns potential acausality/superluminality, whereas the second one arises from the vanishing of the sound speed at specific points during inflation. The former is famously related to positivity constraints on specific EFT operators, derived from dispersion relations on the energy-growing part of scattering amplitudes, and indeed we show that subluminality constraints for the gravitino are related via the equivalence theorem to positivity bounds in low-energy goldstino actions. However, the former are stronger, in the sense that they apply to functions of the scalar fields not only in the ground state, but for any field values such as those scanned by time-dependent solutions, unlike bounds derived from 2 → 2 scattering amplitudes in the vacuum. We also argue that nontrivial causality constraints arise only in the case where nonlinear supersymmetry in the matter sector is encoded into superfield constraints which do not seem to arise from microscopic two-derivative lagrangians, in particular for the orthogonal constraint used to build minimal models of inflation in supergravity. This allows us to propose simple alternatives which maintain the minimality of the spectra and are causal in all points of the theory parameter space. We also discuss minimal supergravity models of inflation along these lines.https://doi.org/10.1007/JHEP11(2022)113SuperspacesSupersymmetric Effective TheoriesSupersymmetry Breaking |
| spellingShingle | Quentin Bonnefoy Gabriele Casagrande Emilian Dudas Causality constraints on nonlinear supersymmetry Journal of High Energy Physics Superspaces Supersymmetric Effective Theories Supersymmetry Breaking |
| title | Causality constraints on nonlinear supersymmetry |
| title_full | Causality constraints on nonlinear supersymmetry |
| title_fullStr | Causality constraints on nonlinear supersymmetry |
| title_full_unstemmed | Causality constraints on nonlinear supersymmetry |
| title_short | Causality constraints on nonlinear supersymmetry |
| title_sort | causality constraints on nonlinear supersymmetry |
| topic | Superspaces Supersymmetric Effective Theories Supersymmetry Breaking |
| url | https://doi.org/10.1007/JHEP11(2022)113 |
| work_keys_str_mv | AT quentinbonnefoy causalityconstraintsonnonlinearsupersymmetry AT gabrielecasagrande causalityconstraintsonnonlinearsupersymmetry AT emiliandudas causalityconstraintsonnonlinearsupersymmetry |