= The first !MadAnalysis 5 workshop on LHC recasting @ Korea = = Analysis 7: ATLAS-EXOT-2016-32 = ||= Students =||Tae Hyun Jung (Analysis Webpage Editor), Kyung Sun Lee, Tae Gun Kim, Seungwon Baek|| || || || || || || ||= Supervisor(s) =|| Guillaume Chalons || || || || || || == 1. Analysis summary == Search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum. Exclusion limits are also placed in models where dark-matter candidates are pair-produced. Models investigated are simplified DM models, an EFT and a high mass scalar resonance. == 2. Analysis global information == * ATLAS contact person: Marie-Hélène Genest (genest@lpsc.in2p3.fr) * Center of mass energy: 13 TeV * Integrated luminosity: 36.1 fb^-1^ * Link to arXiv: https://arxiv.org/abs/1704.03848 * Link to the collaboration page: https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2016-32/ * Link to CDS: * Link to Inspire: https://inspirehep.net/record/1591328 * Other useful links... == 3. Selection description == === 3.1 Trigger selection === The events for the analysis were recorded using a trigger requiring at least one photon candidate above a ET_gamma threshold of 140 GeV to pass "loose" identification requirements. For events in the signal regions defined below, the efficiency of the trigger is more than 98.5%. Events are removed if they contain a bad-quality photon or jet. Events in the signal regions (SRs) are required to have the leading photon satisfying the criteria defined in Section 4 and having ET_gamma > 150 GeV. === 3.2 Object definition === * Photons: The photon identification is based on the profile of the energy deposits in the first and second layers of the electromagnetic calorimeter. Candidate photons are required tohave ET_gamma >10GeV,to satisfy the "loose" identification criteria and to be within |η| < 2.37. Photons used in the event must satisfy additionally the "tight" selection criteria, have |η| < 1.37 or 1.52 < |η| < 2.37. They must be isolated by requiring the energy in the calorimeter in a cone of size Delta R = sqrt((Delta η)^2^ + (Delta Phi)^2^) = 0.4 around the cluster barycentre, excluding the energy associated with the photon cluster, to be less than 2.45 GeV + 0.022 x ET_gamma. * Electrons: They must fulfil the "medium" identification requirement. Electrons are required to have pT > 7 GeV and |η| < 2.47. * Muons: Muon candidates must pass the "medium" identification requirement. Muons are required to have pT > 6 GeV and |η| < 2.7. * Taus: The tau leptons decaying to hadrons and tau neutrinos are considered as jets. * Jets: Jets are reconstructed with the anti-kt algorithm with a radius parameter R = 0.4. Candidate jets are required to have pT > 20 GeV. Jets used in the event selection are required to have pT > 30 GeV and |η| < 4.5. * Overlap removal: If any selected electron shares its ID track with a selected muon, the electron is removed and the muon is kept, in order to remove electron candidates originating from muon bremsstrahlung followed by photon conversion. If an electron lies a distance Delta R < 0.2 of a candidate jet, the jet is removed from the event, while if an electron lies a distance 0.2 < Delta R < 0.4 of a jet, the electron is removed. Muons lying a distance Delta R < 0.4 with respect to the remaining candidate jets are removed, except if the number of tracks with pT > 0.5 GeV associated with the jet is less than three. In the latter case, the muon is kept and the jet is discarded. Finally, if a jet lies a distance Delta R < 0.4 of a candidate photon, the jet is removed. * ETmiss: The missing transverse momentum vector Emiss is obtained from the negative vector sum of the momenta T of the candidate physics objects. Calorimeter energy deposits and tracks are matched with candidate high-pT objects in a specific order: electrons with pT > 7 GeV, photons with ET > 10 GeV, muons with pT > 6 GeV and jets with pT > 20 GeV. === 3.3 Cut-flow chart === === 3.4 Definition of exotic observables === None == 3. Detector simulation == Can we use the last release of the Delphes package with the CMS/ATLAS MA5tune-card? or do need to improve the simulation? == 4. Validation material == === 4.1 Monte-Carlo samples === * LO/NLO? NLO for simplified models of DM, LO for EFT * Model used: Models with DM pair-produced (vector/axial-vector mediator, EFT, high-mass scalar resonance), DMsimp * MC generator program (name + version): MG5_aMC@NLO v2.4.3 for DMsimp, MG5_aMC@NLO v2.2.3 for EFT, Powheg-Box v1 for high mass scalar resonance * Shower program (name + version): Pythia v8.212 for DMsimp, Pythia v8.186 for EFT, Pythia v8.210 for high mass scalar resonance * Tune of Pythia: A14, AZNLO for high mass scalar resonance * PDF set: NNPDF3.0, CT10 and CTEQ6L1 PDF for high mass scalar resonance * ME/PS merging???? === 4.2 Reference plots / cut-flows === See https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2016-32/#tables == 4. Validation results == == 5. Reinterpretation (optional) == == 6. Questions / issues == == 7. Analysis Group Contacts == * Guillaume Chalons:[mail:guillaume.chalons@th.u-psud.fr] * Tae Hyun Jung: [mail:thjung0720@gmail.com] * Kyung Sun Lee: [mail:kyungsun.lee@yonsei.ac.kr] * Tae Geun Kim: [mail:edeftg@gmail.com] * Seungwon Baek: [mail:swbaek@kias.re.kr]