From the detector to physics, and from minimum bias to jets Eric Feng ( University of Chicago) NSF Review 2010 November 2 2010 Nov 2E. Feng (U. of Chicago) - NSF Review2 Introduction University of Chicago has played a central role on the ATLAS experiment Development of remote monitoring system for ATLAS in close collaboration with TDAQ Coordination Central involvement in Jet/EtMiss group on computing, data quality, and jet performance, & calibration Substantial hardware responsibilities for MBTS system Used to trigger most of the first LHC data collected in 2009 and analyzed Leading roles on early jet analyses Inclusive jet and dijet cross-section measurements Search for resonances using dijet mass spectrum Search for contact interactions using dijet angular distribution 2010 Nov 2E. Feng (U. of Chicago) - NSF Review3 MBTS Trigger Hardware work has included substantial responsibilities for optimizing the performance, simulation, and operation of photo-electronics for the Minimum Bias Trigger Scintillator (MBTS) system Used to trigger the vast majority of 2009 data that was collected and analyzed. E. Feng, J. Pilcher. "Triggering ATLAS with Minimum Bias Trigger Scintillators". ATL- TILECAL-INT , CERN. May 2007. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review4 MBTS at 900 GeV (1 of 2) ATLAS Collaboration. "Performance of the Minimum Bias Trigger in p-p Collisions at sqrt(s) = 900 GeV". ATLAS-CONF , CERN. March The single particle response of each MBTS counter was studied using tracks extrapolated through the magnetic field, from the Inner Detector to the MBTS counter. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review5 MBTS at 900 GeV (2 of 2) The calibration constants were fixed in the digitization in order to correct gross discrepancies in the MBTS full simulation due to: incorrectly modeled PMT high voltage miscalculation of the trigger output gain incorrect gain conversions in other readout electronics. The miscalibration of the trigger output due to faulty calibration constants was also corrected Ad-hoc correction factors were avoided For maximum robustness, all corrections were derived based on the characteristics of the detector electronics M. Dunford, EJF, J. Pilcher 2010 Nov 2E. Feng (U. of Chicago) - NSF Review6 MBTS at 7 TeV ATLAS Collaboration. "Performance of the Minimum Bias Trigger in p-p Collisions at sqrt(s) = 7 TeV". ATLAS-CONF , CERN. July EJF, J. Pilcher MBTS 2010 Nov 2E. Feng (U. of Chicago) - NSF Review7 Remote monitoring station (1 of 3) In , we built the first remote monitoring station in ATLAS at the University of Chicago (EJF, C. Meyer, J. Pilcher) Designed to reproduce ATLAS Control Room environment, using the CMS Remote Operations Center at Fermilab as a guide Took remote shifts during M5-M7 combined cosmic runs Other remote monitoring stations since developed at BNL, TRIUMF, etc based on similar design 2010 Nov 2E. Feng (U. of Chicago) - NSF Review8 Remote monitoring station (2 of 3) Proposed and implemented a multi-faceted software framework for remote monitoring currently used by the Collaboration The framework mirrors the ATLAS Partition from the restricted ATLAS Technical & Control Network (ATCN) at Point 1 onto the CERN General Public Network (GPN): S. Kolos, et al. ``Online Remote Monitoring Facilities for the ATLAS Experiment'' (Poster). CHEP 2010, Taipei. October 18-22, 2010. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review9 Remote monitoring station (3 of 3) Benefits: Allow collaborators worldwide to take remote shifts for detector operation and data quality Provides a high performance remote desktop across low latency connections without compromising security on the ATCN Ensures low and sustainable loads on critical information servers at Point1 Allows easy scalability of the system in case of increased usage Simple maintenance of the software by Trigger/DAQ (TDAQ) Coordination Worked closely with TDAQ Coordination and the Monitoring Working Group to evaluate and implement the system Used during data-taking since first LHC beam in 2008 2010 Nov 2E. Feng (U. of Chicago) - NSF Review10 Jet / E t m i s s Performance DPD's Data format initially used to select collision candidates in 900 GeV data. Common data format currently used for jet and missing E T performance studies In , EJF served as the Jet/EtMiss responsible for software development of performance DPDs (Derived Physics Data) Implemented algorithms in the Tier0 reconstruction software to centrally produce Jet/EtMiss performance DPDs for calorimeter, photon+jet, and minimum bias datasets from ESD (Event Summary Data) K. Koeneke, et al. "A New Data Format for the Commissioning Phase of the ATLAS Detector" (Poster). CHEP 2009, Prague. March 21-27, 2009. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review11 Track jets for calorimeter data quality In 2008, track-jets were studied as a means to remediate calorimeter jet and missing E T performance in regions of the LAr or Tile Calorimeter that may suffer power supply failure during actual data-taking Example of removal of missing E T tail through the use of track-jets instead of calorimeter jets in the event of a failed power supply in the LAr Calorimeter: G. Choudalakis, E. Feng. Use of Tracks to Recover Jets in Damaged Calorimeter Regions. ATL-PHYS-INT , CERN. January 2009. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review12 Jet algorithms (1 of 2) Performance of different jet algorithms was studied in dijet and W+jets events with pileup ATLAS Cone has very large underlying event corrections (shown for dijets at left) and sensitivity to pileup (right for W+jets) Support change of default jet algorithm to anti-k T, an infrared-safe clustering algorithm that produces uniform cone-like jets EJF, I. Jen-La Plante, J. Pilcher 2010 Nov 2E. Feng (U. of Chicago) - NSF Review13 Jet algorithms (2 of 2) Jet performance was investigated as a function of the jet finder, input constituent type, and size parameter: Parton-level prediction Hadronization & underlying event corrections Sensitivity to pileup Reconstruction efficiency & purity Jet energy scale & resolution Angular resolution J. Butterworth, T. Carli, et al. "Performance of Jet Algorithms in the ATLAS Detector." ATL-COM-PHYS , CERN. December M. Oreglia taking over as editor of note 2010 Nov 2E. Feng (U. of Chicago) - NSF Review14 Photon+jet calibration of absolute JES (1 of 2) Photon+jet balance for in-situ determination of the absolute jet energy scale, the dominant uncertainty for jet analyses (G. Choudalakis, E. Feng) +jet balance being investigated as technique to determine the absolute jet energy scale and its uncertainty in-situ using early data Balance of jet and photon with 2.8 pb -1 at 7 TeV: 2010 Nov 2E. Feng (U. of Chicago) - NSF Review15 Photon+jet calibration of absolute JES (2 of 2) Radial profile density of tracks and clusters was used to derive a data-driven correction for ISR, out-of-cone radiation, and underlying event Shown below with 2.8 pb -1 for R=0.4, where dominated by OOC G. Choudalakis, E. Feng, A. Messina, L. Pribyl. "In-Situ Jet Energy Scale Calibration Using Direct Photon+Jet Balance". ATL-PHYS INT , CERN. December 2009. 2010 Nov 2E. Feng (U. of Chicago) - NSF Review16 Jet properties & inputs to calibration (1 of 2) Studied inclusive jet, dijet, and multi-jet observables to test description of calorimeters, jets, and missing E T in Monte Carlo (EJF) Jet radial width shown to be wider in data than predicted by MC Monte Carlo description was shown to be satisfactory for jets in |y|