Simplified Models

This databased contains the reference for the top-philic models used in Ref. [1]. More precisely, we enclosed a set of UFO files:

ScalarSinglet_UFO : Contains the interactions and particles corresponding to a scalar, singlet of color, top-philic particle
VectorSinglet_UFO : Contains the interactions and particles corresponding to a vector, singlet of color, top-philic particle
ScalarOctet_UFO : Contains the interactions and particles corresponding to a scalar, octet of color, top-philic particle, also called "sgluon" in the context of supersymmetric theories.
VectorOctet_UFO : Contains the interactions and particles corresponding to a vector, octet of color, top-philic particle.

The definition of the coupling and particles follows closely the Lagrangians written in Ref. [1]. They contain both a scalar and pseudo-scalar interactions with the top quarks for the scalar singlet and scalar octet, and a left-handed and right-handed coupling for the vector singlet and vector octet cases. Each coupling carries a NP order to allow for the classification of the diagrams produced in Madgraph. An important catch that they are defined having in mind the possibility of a complex coupling, and therefore with a hermitian conjugate. As a consequence, when comparing with the Lagrangian from [1] for the scalar particles, one has y_S = (y_L + y_R) and y_P = (y_R - y_L).

The four-top final states in these models must be obtained directly as the final states in the Madgraph generation process, in order to ensure that the interference contribution with the SM processes are correctly included. These models were defined for the python2 versions of Madgraph, they are compatible with the latest versions although you may need to run "set auto_convert_model T" to convert them on-the-fly (or run "convert model <Model with full path>" in the MG command line)

generate p p > t t∼ t t∼ NPˆ2>0 QCD=4 QED=2

Finally, we make also available a UFO file with NLO capability corrresponding to our work Ref. [2] for the case of the scalar octet "sgluon".

sgluon_Full_UFO : Note that it must be used specifically for the process pp → OO, where O is the sgluon, with subsequent top decays handled by, e.g. MadSpin. See Ref. [2] for more details on the required process

While this UFO allows for a full NLO description of the pair production, it cannot be applied the "off-shell" case where one of the sgluon becomes too massive to be efficiently produced at LHC, or if the slguon interaction with the top quarks are too strong.

Effective theory Models

In order to compare EFT and simplified models, we further provide

4TopEFT_UFO: Contains the four-top effective interactions at the dimension 6.

The main difference with previous works and other models in the database is that the operators are written in the broken EW phase, and the basis can therefore be simplified compared to the full SMEFT result. We provide the matching relations with the simplified models and with the correspondence with the usual SMEFT four top operators in Ref. [1]. Note that similarly to the simplified model case, the inclusion of the interference terms while generating the process in MG is critical in obtaining a proper result.

References

[1] L. Darmé, B. Fuks, and M. Goodsell, “Cornering sgluons with four-top-quark events,” Phys. Lett. B 784 (2018) 223–228, ​arXiv:1805.10835 [hep-ph].

[2] L. Darmé, B. Fuks, and F. Maltoni, “Top-philic heavy resonances in four-top final states and their EFT interpretation,” JHEP 21 (2021) 143, ​arXiv:2104.09512 [hep-ph].