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ATLAS Data Preservation and Access

ATLAS Data Preservation and Access. Roger Jones. Data Preservation & Access. Opening data access Preparatory discussions with “management”, CB chair, authorship and Pubcom chairs Has clear implications for authorship/membership rules Needs CB-level discussion

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ATLAS Data Preservation and Access

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  1. ATLAS Data Preservation and Access Roger Jones

  2. Data Preservation & Access • Opening data access • Preparatory discussions with “management”, CB chair, authorship and Pubcom chairs • Has clear implications for authorship/membership rules • Needs CB-level discussion • Past experience says these topics provoke long discussion in the CB! • Common principles proposed by LHC experiment Data Policy Harmonization Group straw man • This has been reviewed by the SIPB and taken to CERN Council to become a “policy suggestion” • A draft policy is with the management for discussion & has been seen by the ICB

  3. ATLAS DMP Organization • Data Preservation now included as part of the upgrade activity planning • May increase the funding options – some evidence already • Data Management Planning is now required by some funders for upgrade grants • Looking at the cost/benefit of various strategies • Resource tensioning with other upgrade activities

  4. Principles for preservation & access • General agreement RAW data is preserved for the experiment and future – open data access is not usually possible even to the collaboration members (level 4 data) and is not proposed for general use • Full reconstruction outputs for analysis might be made available after an embargo period –tbd, but clearly embargo of several years. The resource implications to make this useful are high. (Level 3 data) • We support limited access of samples in simple formats for outreach and teaching (level 2 data) – but these are best integrated to our presenter tools • Techniques like Recast may make data (information) usefully available, although it does not meet all the open access criteria for levels 2 & 3 • We already make data from papers and supporting information available through HEPDAT/Inspire (Level 1 data)

  5. Data Preservation Policies • Data Preservation • There are DP policies implied in the Computing TDRs • conserve all raw data during the lifetime of the experiment • All formats & code used for paper analyses to be archived • Tier 0/1s responsible for the physical preservation • Some tacit belief that older sets may be ‘retired’ • Retired data no longer to be on disk or under active analysis • This may need to be revised e.g. if external access is then granted • Obvious resource implications • First priority to to preserve data for active use by the collaboration

  6. ATLAS DP Practical Steps • Making sure raw data can be reprocessed long-term (Level 4) • Identifying key datasets for ‘unique data’ preservation • Setting up regular reprocessing and validation • This has been underway as a test case for the 2009 data, but progress is slow • Forward/backward compatibility issues illustrated in John Chapman’s talk on simulation release plans14/3/13 • Ensure the capability to run old trigger selections offline • AODfixingwill help (reprocessing at analysis format level) • This means level 4 operations can be applied to level 3 AOD format

  7. Digesting validation results • Must display the results of the validation in a comprehensible way: web based interface • The test must determine the nature of the results • Could be simple yes/no, plots, ROOT files, text-files with keywords or length, ... • Need for semi-automated, detailed physics validation • David South is on ATLAS and was central to the DESY SP and DPHEP activities • Identify the useful common components • Identify the ATLAS-specific elements • Set up CERN-based instance for ATLAS (and others?)

  8. Existing open datasets • The CB has authorized various datasets in (level-2) outreach formats for open use in education/outreach • Event displays for interactive analysis (MINERVA/HYPATIA/LPPP/CAMELIA) • JIVE-XML, root format data • Absolutely not intended for any serious analysis, but illustrative

  9. ATLAS Zpath M(eemm)=123 GeV M(gg)=125 GeV • Master the invariant mass technique • to study and measure the (Z, J/y, U) decaying to l+l- • to search for new physics (Z’) • And Higgs boson in gg and l+l-l+l- • HYPATIA using the ATLANTIS event display • Data from 2011 • 13000 events ~2.5 GB (password protected, 100 open) • 13 data groups/directories, 20 subgroups (A-T), and 50 events/mixed sample/2 students • 50% Z, 30% gg, 10% (J/y,U), 5% Z', 5% l+l-l+l- • Higgs candidate events: • 1 fb-1 and cuts according to ATLAS publication • 125 GeV Higgs MC signals ready to upload • (1fb-1, 10fb-1,25fb-1 )

  10. ATLAS Zpath tests • OPloT: • Mll and/or Mgg and/or Mllll to be discussed locally • Moderator: 1 slide with 3 invariant masses; Invariant mass as a tool to identify particles, to discover new particles, and to search for exotic particles • Web pages updated and measurement ready • http://www.physicsmasterclasses.org/exercises/ATLAS-2013/en/zpath.htm • Introduced Higgs • Described new measurements • Prepared material for instructors, moderators, for discussions, …

  11. OPloT Tests 2013 • Higgs comments • 4l provided without requiring 2l from Z, with lower cut on other pair • gg provide MC with 125 Higgs and background • Upload 125 Higgs MC ((1)&10 & 25 fb-1)

  12. ATLAS W-path with real WW (+H) events • Measurements • Wln • W+/W- ratio • Angular distribution between leptons in WW events • MINERVA program using the ATLANTIS event display • 2011 real data: 693 WW/Higgs candidates (from released 1fb-1) mixed with 5307 W and other background events • Histogram tool • spreadsheet and histogram websites connected with database • New measurement tested

  13. ATLAS W-path • Data from 2011, 1.1fb-1 • 350 should be WW (w/o Higgs)
160 should be ttbar or single top
120 should be Z+Jets50 should be W+Jets15 should be from HWW

  14. gg or e+e-? • Left: pT>1GeV; right pT>5 GeV • 2 apparent tracks pointing to 2 calorimeter objects • Zoom reveals 2-pairs e+e- • information • The conclusion is that the 2 calorimeter objects correspond to 2 photons, which have converted and lead to 4 tracks; the tracks from one pair had less than 3 pixel hits • So, to be classified and entered as gg

  15. Level-2 observations • The applications are all trying to illustrate the analyses and physics in the true context of a detector • They use ATLANTIS as a presenter in most cases, which defines the natural common format • Other formats would require an additional interface, to what benefit? • Use case and resource justification for a common format not clear

  16. ATLAS Analysis Roger Jones

  17. The Generic Analysis Flow

  18. Level 3 • ATLAS has no approved level-3 formats for external use, and such release will require such approval • We are concerned that anything released be useful, not consume large amounts of collaboration effort (both in production and response) • As such, tools like Recast are more attractive • The information incorporates the efficiency, acceptances and corrections – so is robust • It also helps meet the internal requirement of full documentation of analyses

  19. Analysis Practical steps - RECAST arXiv:1010.2506 • Framework developed to extend impact of existing analyses • Candidate for within-experiment and long-term analysis archival, encapsulating the full trigger & event selection, data, backgrounds, systematics • Allow an existing analysis to be reinterpreted under an alternate model hypothesis • Complete information from original analysis, including the tacit information, contained in the data • Not optimized for the new model, but more reliable than a naïve reanalysis? Recast seen as a very promising solution for preserving analyses and useful, cost effective preservation of information – addresses levels ~1-~3

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