Tutorial - Part 1: Our First Model Point Test

The Result

If no error occured, CheckMATE should have produced an output similar to the following: Evaluating Results Test: Calculation of r = signal/(95%CL limit on signal) Result: Excluded Result for r: 1.11899756392 Analysis: atlas_1712_02332 SR: 6j-2600

Let us understand these lines one by one:

As explained before, in the standard setup CheckMATE compares the model prediction to the upper limit by calculating r.
The most important information is told in the Result line, which tells us whether the input model point is excluded or allowed.
The r-value which was used to find the result is given here. If r is larger than 1 it means that one predicts more than is allowed.
The most sensitive signal region (according to the prescription explained on the previous page) that set the limit is given as well.

Since CheckMATE uses the statistical error to weaken its exclusion statement (remember the numerator S-1.96 dS in r), it will produce weaker limits if the statistics is poor. However, if we tried to reproduce the precise exclusion line with r=1, we would need more simulated events to find agreement.

But is this really the best LHC13 could do?

In the above example run, we already told you which of the many analyses you should use for testing and we argued why this analysis should be sensitive to our model. However, maybe CheckMATE contains a different analysis which might have been even more sensitive. Often it might not be obvious at all for the user which analysis is actually the most sensitive. As a simple example, if a BSM decay chain produces W bosons it might not be clear at first if its hadronic or its leptonic decay modes prove to be easier to distinguish from Standard Model. Fortunately, the user does not have to choose a particular analysis. The parameter can be set for example to atlas13TeV or 13TeV, so CheckMATE will automatically test against all implemented 13 TeV results from ATLAS and CMS.

Use your previous CheckMATE input parameter file and change the Analyses keyword and change it to atlas13TeV. Look at the analysis list in data/analysis_info and try to figure out which other analysis can be sensitive to the model
[Show Answer]

With this example, you know all the basics to test your model against LHC results using CheckMATE. The only thing you need to be able to do is using one of the many event generators on the market to produce .hep or .hepmc files plus the corresponding cross sections for the most relevant production times decay scenarios. Then you can straightforwardly put these into CheckMATE to identify excluded and allowed parameter regions.
Click to finish exercise 1.