Abstract
The CMS experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 105. The first level (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High Level Trigger combines fine-grain information from all sub-detectors. To guarantee a successful and ambitious physics program despite the very large backgrounds and proton-proton collision rates, the CMS Trigger and Data acquisition system must be consolidated. In particular the L1 Calorimeter Trigger hardware and architecture will be upgraded, benefiting from the recent microTCA technology allowing the calorimeter granularity to be better exploited in more advanced algorithms. Benefiting from the enhanced granularity provided by the new system, an innovative dynamic clustering technique has been developed to obtain an optimized tau selection algorithm.
Highlights
After the discovery of the Higgs boson in July 2012 [1][2], an intensive work focussing on the measurements of its properties has started
The H → ττ channel plays a particular role, as it is the only way to test the Yukawa couplings between the Higgs boson and the leptons predicted in the Standard Model
During the Run 1 of the LHC, no dedicated τ triggers have been used. During this period, the jet triggers were used to select τ leptons decaying hadronically. This approach will not be adapted to very intense conditions expected for LHC Run II
Summary
After the discovery of the Higgs boson in July 2012 [1][2], an intensive work focussing on the measurements of its properties has started. During the Run 1 of the LHC, no dedicated τ triggers have been used During this period, the jet triggers were used to select τ leptons decaying hadronically. This approach will not be adapted to very intense conditions expected for LHC Run II. The main idea is to develop a dynamic clustering approach relying on the sole calorimeter information as already developed in the case of the e/γ trigger upgrade [4] The implementation of such a sophisticated algorithm benefits from the capabilities offered by the new trigger architecture [4]. In order to adapt the e/γ clustering to the selection of tau induced calorimeter signal, a detailed study of the energy deposit profile in ECAL and HCAL was first performed
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