3 | | To be written |
| 3 | === Author === |
| 4 | Tran Quang Loc |
| 5 | - Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge |
| 6 | - loctranq@gmail.com |
| 7 | |
| 8 | === Description of the model & references === |
| 9 | Gravitons minimally coupled to Standard Model (SM) is described by the theory of SM with weak gravitational perturbations of Minkowski space, in which graviton is suppressed by a factor of two over Planck scale (denoted as kappa). |
| 10 | |
| 11 | In this implementation, we start from the generic Lagrangian and expand the metric in linearised theory up to second-order expansion. The bosonic sector is trivially expanded while the spinor sector makes use of newly introduced vielbein fields and torsion-free spin connections to construct the covariant derivative. |
| 12 | |
| 13 | At first-order, the model can be used to produce the interactions including 1 graviton minimally coupled to SM, i.e. light-by-light scattering in [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.091602/ Phys.Rev.Lett. 127 (2021) 9, 091602]: Katsuki Aoki, Tran Quang Loc, Toshifumi Noumi, Junsei Tokuda, ''Is the Standard Model in the Swampland? Consistency Requirements from Gravitational Scattering'' |
| 14 | |
| 15 | At second-order, the model is useful for processes with 2 gravitons minimally coupled to SM vertices. |
| 16 | === Model files & extensions === |
| 17 | - Main FeynRules file for the 2 gravitons coupled to full SM: 2Gravitons.fr. |
| 18 | - Example of a Mathematica® notebook loading the model and the parameters: 2Gravitons.nb. |
| 19 | - A model for fourth-order formalism is being developed. |
| 20 | |
| 21 | === Validation === |
| 22 | |
| 23 | At first order, the model has reproduced the results from: |
| 24 | |
| 25 | |
| 26 | [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.091602/ Phys.Rev.Lett. 127 (2021) 9, 091602]: Katsuki Aoki, Tran Quang Loc, Toshifumi Noumi, Junsei Tokuda, ''Is the Standard Model in the Swampland? Consistency Requirements from Gravitational Scattering'' |
| 27 | |
| 28 | [https://journals.aps.org/prd/abstract/10.1103/PhysRevD.103.125020/ Phys. Rev. D 103, 125020 (2021)]: Lasma Alberte, Claudia de Rham, Sumer Jaitly, Andrew J. Tolley, ''QED positivity bounds'' |
| 29 | |
| 30 | The model has also been cross-checked with [http://feynrules.irmp.ucl.ac.be/wiki/Spin2/ Spin 2 simplified model]. We found complete agreement. |
| 31 | |
| 32 | At second order, the model has been checked with Graviton + Photon -> Graviton + Photon process. Its amplitudes satisfy crossing symmetric properties and find complete agreement to ones generated by manual inputs of Feynman rules. |
| 33 | |