HiggsToFourLeptonsEV in the ATLAS EventView analysis framework

ATLAS is one of the four experiments at the Large Hadron Collider (LHC) at CERN. This experiment has been designed to study a large range of physics topics, including searches for previously unobserved phenomena such as the Higgs Boson and super-symmetry. The physics analysis package HiggsToFourLeptonsEV for the Standard Model (SM) Higgs to four leptons channel with ATLAS is presented. The physics goal is to investigate with the ATLAS detector, the SM Higgs boson discovery potential through its observation in the four-lepton (electron and muon) final state. HiggsToFourLeptonsEV is based on the official ATLAS software ATHENA and the EventView (EV) analysis framework. EventView is a highly flexible and modular analysis framework in ATHENA and it is one of several analysis schemes for ATLAS physics user analysis. At the core of the EventView is the representative “view” of an event, which defines the contents of event data suitable for event-level physics analysis. The HiggsToFourLeptonsEV package, presented in this paper, prepares the data for the given analysis context on the Analysis Object Data (AOD) files, the event-level physics analysis is performed and finally the output information is written as an Ntuple which can be read in stand-alone ROOT. This paper describes the HiggsToFourLeptonsEV package and its structure as a collection of EVTools and EVModules. It also presents some illustrative results from the SM Higgs baseline analysis, like the SM Higgs into four-lepton mass reconstruction for a nominal Higgs mass of 130 GeV. The lepton reconstruction performance as well as the SM Higgs to four leptons analysis performance is studied in detail, in particular the dependence on kinematics, lepton reconstruction algorithms, isolation cuts and Higgs masses. Finally the paper discusses plans to adapt the code in order to produce Derived Physics Data (DPD) in POOL format which can be read in ROOT or ATHENA, thus following the ATLAS analysis model recommendations.