Simplified models for resonant neutral scalar production with missing transverse energy final states

Additional Higgs bosons appear in many extensions of the Standard Model (SM). While most existing searches for additional Higgs bosons concentrate on final states consisting of SM particles, final states containing beyond the SM (BSM) particles play an important role in many BSM models. In order to facilitate future searches for such final states, we develop a simplified model framework for heavy Higgs boson decays to a massive SM boson as well as one or more invisible particles. Allowing one kind of BSM mediator in each decay chain, we classify the possible decay topologies for each final state, taking into account all different possibilities for the spin of the mediator and the invisible particles. Our comparison of the kinematic distributions for each possible model realization reveals that the distributions corresponding to the different simplified model topologies are only mildly affected by the different spin hypotheses, while there is significant sensitivity for distinguishing between the different decay topologies. As a consequence, we point out that expressing the results of experimental searches in terms of the proposed simplified model topologies will allow one to constrain wide classes of different BSM models. The application of the proposed simplified model framework is explicitly demonstrated for the example of a mono-Higgs search. For each of the simplified models that are proposed in this paper we provide all necessary ingredients for performing Monte-Carlo simulations such that they can readily be applied in experimental analyses.

Automated summary

This study focuses on extensions of the Standard Model and additional Higgs bosons, developing a simplified model framework to facilitate future searches for particles beyond the SM. By classifying decay topologies and considering different possibilities for mediator spin and invisible particles, it is shown that different simplified model topologies have only minor differences in kinematic distributions but significant sensitivity in distinguishing between decay topologies. The proposed simplified model framework can help constrain a wide range of BSM models in experimental analyses.