A Study of Dark Matter Models at $\sqrt{s}$ = 13 TeV pp Collisions for Mono-Lepton Searches

A significance study considering new physical findings in proton proton collisions with leptons and missing transverse energy (E6T ) in the final state is performed for a center of mass energy of 13 TeV. The discovery of Dark Matter (DM) is one of the main tasks of the LHC analysis for 13 TeV and 14 TeV data. As well as other discoveries like large extra dimensions and quantum black holes DM has a signature which shows a large imbalance in transverse energy. An analysis of the DM production in CMS at generator level is performed. This analysis uses a simplified model where the DM particle is assumed to be a weakly interacting massive particle (WIMP) and is directly produced by a mediator particle (med). This DM particle is assumed to be a Dirac fermion. The process is studied in different ways, in terms of cross sections (xsecs) and shape, concerning different coupling structures and strengths for the mediator particle coupling to Standard Model matter (in the following called matter) and DM. We will study three different mediator models. These models distinguish in the structure, how the mediator particle couples. These models are the axialvector (AV), scalar (S) and pseudoscalar (PS) model. Whithin these models, we will vary the coupling strenght. Former analyses assumed that the coupling strengths DM↔med and matter↔med are equal in the DM generation process. Such an analysis concerning different coupling structures and different coupling strengths for DM↔med and matter↔med has never been done before. It shall extend the assumptions about the coupling structure and strength in former papers, to ’fully map out the MSDM1 landscape’ [1]. Different mediator and DM masses are discussed in the background of this simplified model as well. To connect the generator level processes with the experiment, full simulations with respect to the CMS system are done. Then the expected limits can be set into the parameter space of the simplified model. This paper shows that the different couplings scale the cross section in dependence of the coupling strength but provide new analysis methods when concerning the difference in the shape of the signals for different coupling structures. It shows, that the difference in cross section and shape concerning different coupling structures are huge. We show that the AV model is the best model to study processes with a heavy mediator particle and the PS is the best model to study processes with relatively light mediators.