Topology Coverage

The constraints provided by SModelS are obviously limited by its database and the available set of simplified model interpretations provided by the experimental collaborations or computed by theory groups. Therefore it is interesting to identify classes of missing simplified models (or missing topologies) which are relevant for a given input model, but are not constrained by the SModelS database. This task is performed as a last step in SModelS, once the decomposition and the theory predictions have been computed.

Given the decomposition output (list of elements), as well as the database information, it finds and classifies the elements which are not tested by any of the experimental results in the database. These elements are grouped into the following classes:

• missingTopos: elements which are not tested by any of the experimental results in the database (independent of the element mass). The missing topologies are further classified as:

  • longCascade: elements with long cascade decays (more than one intermediate particle in one of the branches);
  • asymmetricBranches: elements where the first branch differs from the second branch (but that are not considered as long cascade decays).

• outsideGrid: elements which could be tested by one or more experimental result, but are not constrained because the mass array is outside the mass grid;

In order to classify the elements, the tool loops over all the elements found in the decomposition and checks if they are tested by one or more experimental results in the database [*]. All the elements which are not tested by any of the experimental results in the database (independent of their masses) are added to the missingTopos class. The remaining elements which do appear in one or more of the experimental results, but have not been tested because their masses fall outside the efficiency or upper limit grids (see EM-type results and UL-type results), are added to the outsideGrid class.

Usually the list of missing or outsideGrid elements is considerably long. Hence, to compress this list, all elements differing only by their masses (with the same final states) or electric charges are combined. Moreover, by default, electrons and muons are combined to light leptons (denoted “l”): gluons and light quarks are combined into jets. The missing topologies are then further classified (if applicable) into longCascade or asymmetricBranches topologies.

The topologies for each of the four categories are then grouped according to the final state (for the missingTopos and outsideGrid classes) or according to the PDG ids of the initially produced motherparticles (for the longCascade and asymmetricBranches classes). We note that for the latter the elements deriving from different mother particles, but with the same final states and mass configuration cannot be distinguished, and are therefore combined in this grouping. The full list of mother PDG id pairs can be accessed in the python printout or the comment of the text printout.

The topology coverage tool is normally called from within SModelS (e.g. when running runSModelS.py) by setting testCoverage=True in the parameters file. In the output, contributions in each category are ordered by cross section. By default only the ones with the ten largest cross sections are shown.

• The topology coverage tool is implemented by the Uncovered class

[*]	If mass or invisible compression are turned on, elements which can be compressed are not considered, to avoid double counting.