UBC Undergraduate Research

Adding Ƭ leptons to the search for supersymmetry in events with three leptons and missing transverse momentum with the ATLAS detector at the LHC Boone, Kyle


The objective of this project was to investigate adding taus to the search for supersymmetry with the ATLAS detector at the LHC. This analysis was done using the framework set up by the group investigating the channel with a final state with 3 leptons where none of them are Ƭ leptons. I modified this framework to include Ƭ leptons and performed all of my analyses using the framework. I began by studying the reconstruction of Ƭ leptons. These particles are very short lived and only their decay products are observed in the detector so they must be reconstructed in the analysis. After determine a suitable reconstruction method I investigated reproducing an analysis similar to what has been done with the 3 light leptons in order to improve the sensitivity to the models targeted by that search. Adding taus in proved to yield much weaker results than the standard 3 light leptons search and did not yield any significant increase in sensitivity. I then investigated a final state where there are two same sign light leptons and one tau. This configuration results in a much smaller background than the standard 3 lepton search. I identified several models where this search would be able to outperform the 3 light lepton search and optimized signal regions for these models. Supersymmetry is a very promising theory for physics beyond the Standard Model and current searches have little to no sensitivity to the chosen configuration which motivates the addition of new channels. I began work on the background estimation but ran into some issues that the ATLAS SUSY multilepton group is currently trying to figure out. The new signal regions that I have found have been included in the analysis of the full 2012 dataset.

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