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DOE REVIEW

DOE REVIEW. Wisconsin at ATLAS (1) Overview and Higgs. Sau Lan Wu. For the Wisconsin Task H. May 15, 2007. Outline. Overview Higgs at ATLAS ATLAS Computing. Sau Lan Wu. SUSY and Exotics searches in ATLAS. Yibin Pan. LHC and ATLAS status Silicon Read-out Driver

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DOE REVIEW

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  1. DOE REVIEW Wisconsin at ATLAS (1) Overview and Higgs Sau Lan Wu For the Wisconsin Task H May 15, 2007

  2. Outline • Overview • Higgs at ATLAS • ATLAS Computing Sau Lan Wu • SUSY and Exotics searches in ATLAS Yibin Pan • LHC and ATLAS status • Silicon Read-out Driver • High Level Trigger • Detector performance and software development Bruce Mellado • BaBar Yibin Pan

  3. Overview: Manpower distribution Faculty: Wu (Professor), Pan (Associate Professor with tenure 2004) & Mellado (Assistant Professor 2006) Scientist:Zobernig (ATLAS) Assistant Scientist: Padhi (ATLAS) ATLAS Postdocs:Flores, Sarangi, Peng Five Grad Students:Stradling (ATLAS), Quayle (ATLAS), Fang (ATLAS), Zhou (ATLAS), X. Chen (ATLAS/BaBar) - A new student just joined: Matthew Gonderinger Supported by ATLAS M&O funds: Software Engineers:Wiedenmann , Dos Anjos, Xu, Vickey (part-time) Engineers:Jared, Joseph, H. Chen (all part-time) (It is expected that both numbers above will be reduced in FY08, FY09 and FY10.)

  4. Overview: The BABAR experiment • In September 1995, our group joined the BaBar Collaboration at PEP II. • After having made contributions to both BaBar detector construction • and software development in the silicon vertex tracker, we are • privileged to have played a crucial role (in particular in flavour tagging • of or ) in the 2001 discovery of large CP violation in the B meson • system. • In the last few years, we have concentrated on : • Measurement of the CKM angle α • Decaysdominated by s-penguin processes which are sensitive to new physics • Rare and exotic B decays (Bτυand search for charmed pentaquarks) • Yibin Pan and our former postdoc Mathew Graham have been • convenors for the Charmless three-body physics working group. • Due to continuous funding reductions over the past three years (25% in • total) in our base program and the imminent turn on of the LHC, it is • necessary to redirect most of our efforts to ATLAS.

  5. Overview: Ph.Ds with the BaBar experiment We have granted 10 Ph.D. degrees in BaBar – 8 of them in 2004-2006 From 2004 to 2006 Before 2004 Redirection: Professor Pan: - from full time in BaBar to almost full time in ATLAS Postdocs: - Haibo Li left BaBar to IHEP, Beijing - Now Full Professor and Physics Coordinator of BES III - Matthew Graham still works with our BaBar effort but is paid by SLAC

  6. Overview: The ATLAS experiment • In September 1993, our group joined the ATLAS collaboration at LHC. • We were the first American group to join the collaboration. • Our contribution to ATLAS focuses on: • We are fully responsible for the design, production and commissioning of the Read-out Driver (ROD) system for pixel and silicon strip detectors. • We play a leading role in the design, development, implementation and commissioning of the ATLAS High Level Trigger. • We are making a vigorous effort to contribute to the ATLAS computing operations. • We are making important contributions to detector performance studies and software development in ATLAS. • At present, our group plays a leading role in the ATLAS Higgs studies. Our main focus is to continue our leadership in the observation of the Higgs at the LHC and to expand our effort to SUSY and exotic particle searches.

  7. Overview: The ATLAS experiment To position ourselves to make important contributions to ATLAS for early discovery, we have at least one member of our group who gains expertise and makes contributions to: * Electron identification (e/π rejection) and energy calibration (L. Flores) * Photon identification (/jet rejection) and energy calibration (B.Mellado and Y. Fang) * Calorimeter based muon identification (L. Flores) * Hadronic and in-situ jet energy calibration (S. Padhi) * Missing transverse energy reconstruction (B. Mellado and X. Chen) * B-tagging (Y. Pan) * Trigger (H. Zobernig) * Computing and grid middleware (S. Padhi) * Statistics tools (W. Quayle) * Monte Carlo events generation with full detector simulation (B. Mellado and S. Padhi)

  8. Education: Recent Faculty Appointments 2004-2007: Six NEW faculty appointments have been awarded to our former postdocs and former graduate students: Haibo Li (2005) Full Professor at IHEP, Beijing Stathes Paganis (2005) Lecturer at University of Sheffield, UK (tenure) Jason Nielsen (2006) Assistant Professor at UC Santa Cruz Bruce Mellado (2006) Assistant Professor at University of Wisconsin Jane Nachtman (2007) Assistant Professor at University of Iowa (former Fermilab Wilson fellow) Kyle Cranmer (2007) Assistant Professor (offers at New York University and StonyBrook); (presently Goldhaber fellow at Brookhaven)

  9. 10 TASSO 22 ALEPH 10 BaBar 2 ATLAS Education: Training of Graduate Students 44 Grad. students have obtained Ph.D. degrees from this task:

  10. Education: Faculty Positions of Former Postdocs and Grad Students 26 Former Postdocs and Graduate Students are (or have been) faculty members mainly in major U.S. universities and 10 are permanent staff members at major High Energy laboratories. (12 full prof., 7 associate prof. with tenure, 5 assistant prof. and 2 former assistant prof.) Associate Professors with tenure Full Professors Assistant Professors ATLAS: 9 CMS: 4

  11. Talks given by group members (1) Conferences and Workshops 2004-present TOTAL = 78 (2) ATLAS Working Groups 2004-present TOTAL = 425

  12. Wisconsin Contribution to the ATLAS Physics Workshop Rome, Summer 2005 • This physics workshop was the biggest event in the ATLAS calendar in • physics-related assemblies, with an unprecedented number of 450 participants • Wisconsin was the university group with the largest contribution in the • ATLAS Collaboration • We gave six plenary talks (there were a total of 20 talks from US institutions) • Our work was presented in 16 plenary talks, spanning over 5 different • physics and performance Working Groups • In total our work was mentioned 72 times by speakers at the Rome workshop Since Rome, we have expanded our physics preparation effort to get ready for: 2008 – Calibrations 2008/2009 – Understand Standard Model & QCD Background SUSY, New Gauge bosons W’, Z’ Other new particles – high energy frontier 2009/2010 – Higgs Discovery: We cover all important channels and the full mass range

  13. Higgs In the fall of 2000, the first possible evidence of a Higgs boson signal at 115 GeV/c2 in ALEPH, which drew so much public attention is largely the work of our Wisconsin group. The final state observed was four jets and the ALEPH published significance was 3σ. One of the exciting prospects for the LHC is to confirm or reject this observation. Low mass Higgs is preferred

  14. Tag jet Tag jet Forward jets f h Higgs Decay Low Mass Higgs Associated with Jets Inclusive H+1jet H+2jet Tag jet Not tagged Tag jet VBF (Vector Boson Fusion): Proposed by Wisconsin Pheno. Not Tagged Not tagged H+1 jet: proposed by our group for H, HWW(*) and HZZ(*). Analyses in TDR were mostly inclusive Mellado, Quayle, WU Phys. Lett. B611:60-65, 2005

  15. H+2jet H+1jet Inclusive 10 fb-1 30 fb-1 30 fb-1 Mγγ(GeV) Mγγ(GeV) Mγγ(GeV) H→gg Inclusive and H→gg with 1, 2 jets • Wisconsin is a leader of ATLAS inclusive analysis. Bruce Mellado is • the convenor of the ATLAS H group. • We also pioneered a new analysis strategy (adopted in ATLAS) • We have proposed to ATLAS an analysis strategy based on the • classification of events according to jet multiplicity, i.e H+0, 1, 2 jets • Background extracted from data and fit-based analysis are • performed.

  16. H+0,1,2 jets H+0,1 jets 5σ Inclusive H→gg : Combined H→gg with 0, 1, 2 jets Our group’s work has improved the sensitivity of this channel by about a factor of two

  17. H + 1 jets H + 2 jets Tagging Jets Higgs Decay Products     Quasi-central Tagging Jet Loose Central Jet Veto (“top killer”) Higgs Decay Products Central Jet Veto H→tt :Low MassH→tt with 1, 2 jets Because of the poor Higgs Hττ mass resolution, inclusive analysis is not possible. Need to reduce QCD backgrounds by using distinct topology of associated jets.

  18. Hll MH=120 GeV H→tt :Low MassH→tt with 1, 2 jets Reconstruct Higgs mass with collinear approximation H(ll) +1jet B.Mellado, W.Quayle and Sau Lan Wu Phys.Lett.B611:60-65,2005 H(ll) +2jets (VBF) 30 fb-1

  19. Z + jets e+e- H→tt : A Background Control Sample for Hττ • We use events that can be triggered on easily and efficiently • Z→ee and Z→μμ (+jets) events are taken from ATLAS data; we scale-back the lepton momentum and decay the leptons as taus to model the Z → ττ background: e e e e    

  20. H→tt :H + 1,2 jets in Full Simulation

  21. HZZ(*) 4 leptons • This “golden” channel is the most powerful • discovery channel for 2MZ < MH < 300 GeV Colors: Signal QCD ZZZbbtt H4l (4e+4µ+2e2µ), 10 fb-1, NLO: mH = 130 GeV mH = 150 GeV Higgs Higgs ZZ ZZ

  22. HZZ(*) 4 leptons In parallel to the sliding-cut strategy (different cuts for different Higgs mass hypotheses), our group is the first one in ATLAS to study the potential of a global fit for this channel to increase sensitivity Higgs signal (130GeV) QCD ZZ Higgs signal (130GeV) QCD ZZ Probability Unbinned maximum likelihood fit to a toy MC outcome for 30 fb-1 (M4l projection)

  23. HZZ(*) 4 leptons (using NLO cross sections) 5σ

  24. H WW: HWW(*) with 0,1,2 jets • These are the most important final states for MH>135 GeV • We have pioneered the use of HWW(*) associated with one high PT jet • Leading jet in signal is more forward than in background • Adds significant sensitivity and it is complementary to HWW(*) associated with 0 and 2 jets • Developed a new Data-Driven method to extract background and pioneered the use of the global fit-based method • Extended applicability of these final states to Higgs close to the LEP limit • William Quayle is the convenor for the HWW group

  25. 10 fb-1 H  WW 5σ H WW: HWW(*) with 0,1,2 jets • Wisconsin has designed a robust analysis, which combines the three final states • - Significance enhanced by about 75%

  26. HWW H→ZZ(*) Higgs: Contribution to Statistics Tool for Higgs in ATLAS Our leadership in the area of statistics tools for Higgs searches at LEP enable us to create a package for ATLAS using advanced statistical treatments to combine all the important channels in the Higgs studies. ATLAS Preliminary Sensitivity to light Higgs has more than doubled largely due to the efforts of the Wisconsin group Combined Combined William Quayle has been selected to be a member of the ATLAS Statistical Forum ATLAS can reach a 5σ signal significance for MH>114 GeV with only 10 fb-1of data with simple cut analysis (7 fb-1 with neural network)

  27. ATLAS can reach a 5σ signal significance for high mass Higgs with only 7 fb-1of data Work of the Wisconsin group

  28. Contribution to ATLAS Computing Operations The computing operation for LHC has entered a new and unprecedented era – the problem of scalability In 2004, I have initiated the collaboration with the Wisconsin Computer Science department, Professor Livny’s team, inspired by the successful example of Profs Smith and Dasu. Livny is one of the two directors of the Open Science Grid. This collaboration has proven to be extremely successful, for example: • For the ATLAS Physics workshop in June 2005, our group led by Bruce Mellado generated 10M fully simulated events in Wisconsin, available to the ATLAS collaboration, more than the total produced by ATLAS.

  29. Contribution to ATLAS Computing Operations • A prototype of new Grid technology was designed and deployed by our group member, Sanjay Padhi, on the Open Science Grid in order to study inclusive SUSY signals. He was able to reach several thousands of unused CPUs each day(215 CPU years in less than two months) to calculate the Standard Model background for SUSY processes. Ruth Pordes, the other director of OSG, has featured Sanjay’s achievements in the OSG newsletter in January 2006

  30. Contribution to ATLAS Computing Operations (3) The creation of the grid execution system CRONUS – The ATLAS Management recruited Sanjay Padhi to deploy CRONUS to integrate the production systems of the nine Tier 1 clouds. Instead of working with a large number of inhomogeneous grid submission systems, the users can use only one grid submission system, i.e CRONUS. Taiwan Canada France Nine Tier 1 Clouds Germany Netherlands Nordic countries Spain UK Italy • The technology used by CRONUS is Condor glide-in in collaboration with Prof. Livny. • This demonstrates the power and opportunity for innovation of interdisciplinary collaboration across university campuses – between Physics and Computer Science, also CMS and ATLAS

  31. Cronus (in yellow) started massive production Feb. 15th 2007 ATLAS Job Production monitoring graph shown by P. Jenni (ATLAS spokesperson) in ATLAS collaboration week, Feb. 23rd 2007

  32. Convenorships and Positions of Responsibility

  33. Convenorships and Positions of Responsibility

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