A universal framework for t-channel dark matter models

Abstract

We present the model implementation in FeynRules, which aims to offer a unique general framework allowing for all simulations relevant for simplified t-channel dark matter models at colliders and for the complementary cosmology calculations. We describe how to match next-to-leading-order QCD fixed-order calculations with parton showers to derive robust bounds and predictions in the context of LHC dark matter searches, and moreover validate two model restrictions (relevant for Dirac and Majorana fermionic dark matter respectively) to exemplify how to evaluate dark matter observables to constrain the model parameter space. More importantly, we emphasise how to achieve these results by using a combination of publicly available automated tools, and discuss how dark matter predictions are sensitive to the model file and software setup. All files, together with illustrative Mathematica notebooks, are available from the URL http://feynrules.irmp.ucl.ac.be/wiki/DMsimpt.

Review on Dark Matter tools

“…Review on Dark Matter Tools Chiara Arina see [15][16][17][18][19]. From the same model Lagrangian, F R provides output files for computing collider predictions with MG5_ MC [20] (UFO format [21], the same used in M DM) and to apply collider bounds with the recasting tool M A 5 [22].…”

“…For instance, in refs. [19,39] the discrepancies in the relic density calculation arise in the different treatment of the QCD sector in MG5_ MC and C H . In summary, in the standard WIMP freeze-out scenario, all public codes have been deeply tested and compared, process that has allowed to solve numerous bugs.…”

“…This ability is based on M L [105]. A first attempt in the automatisation of loop-induced processes is presented in [19], however the code is currently being tested before its public release, which is foreseen for early 2021. The relevance of loop-induced processes is striking for dark matter observables: since the dark matter is neutral it can not couple directly to photons, hence the annihilation into di-photon can proceed only via loop (or effective vertex).…”

Contact interactions and top-philic scalar dark matter

“…This occurs via a t-channel interaction originating from an ST t operator. Many scalar DM models including a t-channel fermionic mediator have previously been studied [5][6][7][8][9][10][11], as top-philic DM models [12][13][14][15][16][17][18] and heavy DM with masses ranging up to several TeV have been discussed in the literature [19]. In particular, recent investigations [9,10] have shown that while leading order (LO) calculations allow for a heavy DM, next-to-leading-order (NLO) corrections to the annihilation cross section lead to significant modifications of the existing constraints on the model parameter space.…”

“…Figure11. Results of our fitting procedure for an example mass point featuring m S = 682.6 GeV, with varying r values (top row and bottom left figures), and the corresponding exponential fit to the deviation (bottom right).…”