Fermilab Roles in DØ Physics u u Adam

Fermilab Roles in DØ Physics u u Adam Lyon for the DØ Fermilab Group May 2006 Outline u Introduction to the Fermilab Group at DØ u Highlight Fermilab’s role in. . . v. DØ Organization v. Support for Physics Analyses v. The DØ Physics Program

Fermilab Group at DØ u One of 92 user groups on DØ u 54 members (out of 671), largest group v v v Particle Physics Division: 44 Computing Division: 7 Accelerator Division: 1 Technical Division: 1 Visitor 1 (6 Postdocs, 2 Wilson Fellows, 1 Lederman Fellow) (1 Postdoc, 1 Associate Scientist) u Two representatives and votes on the Institutional Board (only group with 2) u Also, DØ has 3 Guest Scientists v 2 PPD, 1 CD (+1 more CD coming soon) v Fermilab provides assistance to enable work for a particular duty or task (e. g. Computing & Software Head, help with Monte Carlo system) v Guest Scientists stay with home institution A. Lyon (DOE Program Review, May 2006) 2

Roles of the DØ Fermilab Group u Crucial contributions to. . . v v u Detector operations and management Infrastructure (Detector & Computing) Physics software & Data handling Physics Analyses Physics v Analysis choice based on personal interest v ~20 members in an active physics analysis v ~10 papers (of 41 accept+subm) have Fermilab Group member as a primary author v ~22 members involved in physics reviews • 36 Editorial Boards • 5 have chairs from Fermilab group u Fermilab group contributions have been and continue to be critical to the success of the DØ experiment A. Lyon (DOE Program Review, May 2006) 3

Leadership Roles in DØ Organization Spokespersons G. Blazey T. Wyatt Technical Integration Coordinator G. Ginther Run IIb Upgrade Run Coordinators V. O’Dell R. Lipton (deputy) Silicon Layer O W. Lee T. Yasuda (3/4) Trigger (1/6) DAQ/Online (2/3) Installation (2/2) AFEII-t Advisory Council Chair: J. Hays Institutional Board Chair: D. Wood Special Projects G. Gutierrez Computing and Core Software G. Davies Outreach and Public Tour Area G. Snow D. Lincoln Software Algorithms M. Hildreth S. Kappler M. Ford Production (5/8) Algorithms Groups (3/15) Analysis (2/4) Data Quality Authorship Committee Chair: Alan Jonckheere Physics J. Hobbs V. Buescher (deputy) Physics Groups (3/6) Executables (1/5) Working Groups (1/3) Subdetectors (1/7) Subdetectors (3/8) Speakers Bureau Chair: A. Zieminski Trigger Board/TM Editorial Boards Online L 3/DAQ u In past 3 years, Fermilab Group members have served in all high level posts u FNAL/DØ scientists in Fermilab leadership posts v PPD DØ Department v Department head of CD/Running Experiments v Project Manager of CD/SAMGrid v Group Leader of ILC Detector R&D Trigger (1/4) Online Monitoring A. Lyon (DOE Program Review, May 2006) 4

Fermilab Roles Supporting DØ. . . Run Operations (one Run Coordinator is from Fermilab Group) ~87% eff for past year 1. 41 fb-1 delivered Much thanks to Accelerator Division 1. 19 fb-1 recorded to tape 84. 4% efficiency overall u Silicon u v S/N > 10 for all devices v >97% cluster reconstruction eff, < 15% mortality (stable, no fiducial loss) u v v Tracker & Preshowers v 1% of VPLC channels non-functional v Solenoid slightly degraded, but stable at 4550 A (not 4750 A) for past year A. Lyon (DOE Program Review, May 2006) Calorimeter u 99. 5% of 55, 000 ch on Cell-by-cell calibration of EM and Had Z ee inv mass res 15% improvement Jet energy res 15 -25% improvement Muon v Stable (to 1%) and very efficient 5

Another example. . . Reconstruction Program u Fermilab Group members responsible for Physics reconstruction program, “reco” v Many collaborators contribute to algorithms and code within reco u Needed speedup to process high luminosity running v Nonlinear and catastrophic rise in CPU time with luminosity v Enlisted help from Fermilab/CD computing experts • Wrote profiling tool • Examined hot spots u Many improvements v ~15% from fixing inefficient code v ~15% from improved tracking algorithm v No loss of efficiency or Physics v CPU time increase with luminosity now ~linear (observed out to ~170 e 30) A. Lyon (DOE Program Review, May 2006) u Fermilab group members responsible for running and maintaining reconstruction farm v 1. 25 THz of CPU v 30 M events/week v Events processed 2 -3 days after collection v Migrating to more standard submission and operating tools v Migrate to lab wide “Fermi. Grid” soon 6

Another example. . . SAMGrid u u Current computing model and planning are very successful SAMGrid (Computing Division) u v 1 B events processed from raw at 12 sites in 6 months v 250 TB out to sites, 70 TB back to FNAL v Data Handling system (started at DØ in 2000, now used by CDF and MINOS too) v Job management system using standard Grid services (where available) and protocols v 6 B events served / week to users v 1. 6 pb of data on tape! Reprocessing u Refixing v 1. 5 B events processed at 7 “sites” in 5 weeks! (finished 1 week early) v 80 TB out, 80 TB back in 5 weeks! v 50% offsite v A First: Used other Grids (LCG & OSG) in an automated way u MC Production v All offsite v Automation with SAMGrid led to significant increase in MC production rate (10 M events/week, 150 M since October) SAMGrid (DØ’s Grid) u LCG OSG u A. Lyon (DOE Program Review, May 2006) Continuing to improve our ability to interoperate with other Grids in automated ways As Grid services mature, we use them instead of our home-written services 7

Physics Questions The Tevatron is THE place for exploring the fundamental nature of matter u v Are there new laws or symmetries? v Extra dimensions? v Unification? v What happened to anti-matter? v Why are there so many types of particles? Are there more? u The Standard Model is confirmed to a remarkable level, but. . . v We know it is incomplete (e. g. hierarchy problem) v We have yet to observe the Higgs v Is there anything else out there? A. Lyon (DOE Program Review, May 2006) 8

DØ Physics and Goals The DØ detector is especially well suited to explore these questions Central Tracking System Central tracker in ~2 T solenoid v. Silicon Tracker | | < 3 v. Scintilating Fiber Tracker | | < 1. 5 Central and Forward Preshowers LAr/U Calorimeter | | < 4. 2 u General high p. T physics detector emphasizing. . . v Lepton Identification (e, , ) v Jets and Missing Transverse Energy v Jet flavor tagging via displaced vertices and leptons A. Lyon (DOE Program Review, May 2006) u Goals: 3 Layer muon system with toroid magnet | | < 2. 0 v Precision tests of Standard Model (W, Z, top, B Physics, QCD) v Search for Physics Beyond the Standard Model (Higgs, SUSY, leptoquarks, quark substructure, extra dimensions, . . . ) 9

QCD Physics u Jets u Improve understanding of proton structure v Parton distribution functions v Quark compositeness u Measure section 8 orders of magnitude! are dominant background for many analyses indicates Fermilab group involvement inclusive jet cross v Improvements in jet energy scale reduced systematic uncertainties by factor of 2 v Further improvements are coming A. Lyon (DOE Program Review, May 2006) 10

Heavy Flavor Production and Decays Important tests of Standard Model u Complements B/charm factory measurements u DØ’s large muon acceptance and forward tracking important! u 10 new results with ~1 fb-1 ! u Heavy Flavor Properties v First measurement of semileptonic u v Limits on FCNC Charm Decays @ 90% CL v First observation of excited B mesons B 1 and B 2* as separated states v First direct observation of Bs 2*0 v Observation of v Search for (Submitted to PRL) A. Lyon (DOE Program Review, May 2006) 11

Bs Mixing u Study unitarity triangle u Complement B factories u B mixing. . . v In SM explained by box diags v Constrains Vtd and Vts of CKM matrix – related to angles u Bs oscillations D+ Ds 7. 4 k 26. 7 k events v. Reconstruct Bs decay for final flavor via Bs Ds v. Determine lifetime of Bs in its frame v. Determine initial flavor from recoil system WORLD’S FIRST v Sensitive to new physics (new particles in the box) 17 ms 21 ps-1 @ 90% CL v md / ms free from many theoretical uncertainties A. Lyon (DOE Program Review, May 2006) 12

Other B mixing/CP related analyses u u Lifetime difference in Bs via ps-1 u Bd mixing with opposite side flavor tagging u Dimuon charge asymmetry (gives B 0 mixing CP violation parameter) A. Lyon (DOE Program Review, May 2006) 13

Electroweak Physics u u u Precision tests of Standard Model with W/Z cross section and mass Test SM and search for new Physics with W/Z+jets, multiboson production, asymmetries Produce large samples of clean high PT leptons for studies and calibrations W Z u u A. Lyon (DOE Program Review, May 2006) Good agreement with SM NNLO Perhaps use to complement luminosity measurement 14

More Electroweak u u Many results close to release Comparison of Z+jets to simulations (950 pb-1) v Pythia, deviates from data! u W Asymmetry v Benefits from wide muon coverage at DØ v Sherpa (parton shower + matrix element), more consistent! v Constrains parton distribution functions A. Lyon (DOE Program Review, May 2006) 15

Diboson: e. g. W u Standard Model gauge theory fixes couplings u Deviation from SM indicates new physics v Measure production cross section and radiation zero v Also leads to study of anomalous moments of W u Analyze W e & W final states u Radiation amplitude zero: v Via interference of leading order diagrams v ud W+ has zero at cos cm = – 1/3 v du W– has zero at cos cm = +1/3 v Remains unobserved u We measure. . . v Charge signed pseudo-rapidity difference between lepton from W and photon in lab frame v Anomalous moments spoil cancellation v Tevatron is best place to look (at LHC NLO corrections are higher, spoiling cancellation) A. Lyon (DOE Program Review, May 2006) 16

Top Quark Physics u Discovered in Run I; continue to study with increasing precision in Run II u Different decays lead to different analysis techniques v Di-lepton: low background, low yield v Lepton+jets: W+jets bkg, b tagging helps! v All Jets: Highest yield, punishing backgrounds (QCD jets) u A. Lyon (DOE Program Review, May 2006) Cross sections consistent across channels. Future improved precision may show discrepancies due to new Physics 17

Top Quark Physics u. Mass is a fundamental parameter of the SM u. Sophisticated analyses v l+jets: Matrix element method v Dilepton: Neutrino weighting v Dilepton, l+jets: Templates v. . . u. Expect u. Other mt ~ 2 Ge. V for 2 fb-1 Top Quark Properties v Charge Q=– 4/3 excluded at 94% CL v W helicity (new physics in t Wb? ) u. Single top v Directly sensitive to new physics in t-W-b vertex v More sophisticated analysis with full dataset is underway Consistent with SM v R = B(t Wb)/B(t Wq) SM predicts R=1 Measure A. Lyon (DOE Program Review, May 2006) 18

Higgs Search u u u Predicted by SM, but not yet observed; constrained by m. W, mt At 8 fb-1, CDF+DØ could observe (3 ) 125 Ge. V Higgs or exclude < 180 Ge. V @ 95%CL Combination of 14 DØ analyses v SM level x 6 - x 15 below limits v Not yet achieved design sensitivity. 2 fb-1 and more sophisticated analyses with more channels may get closer u Example channel A. Lyon (DOE Program Review, May 2006) 19

Non-Standard Model Higgs Searches u u 2 Higgs doublets in most extensions to SM (e. g. MSSM); Gives 5 Higgs particles (3 neutral + 2 charged) If tan is large, cross section may be enhanced over SM by many orders of magnitude; neutral Higgs degenerate ( ) Combined and b(b) bbb(b) A. Lyon (DOE Program Review, May 2006) 20

Supersymmetry Searches u u u SUSY solves the hierarchy problem (fine tuning to avoid scalar loops) Predicts partners for SM particles (none observed so far) In some models, lightest SUSY particle (LSP) is weakly interacting – candidate for dark matter Plethora of phenomenological models (MSSM, super-gravity, gravity mediating, . . . ) Some recent results. . . GMSB SUSY with Diphotons Stopped Gluinos A. Lyon (DOE Program Review, May 2006) 21

SUSY Search Results Stop Pairs A. Lyon (DOE Program Review, May 2006) Squarks and Gluinos 22

Non-SUSY Search Examples Excited Muons A. Lyon (DOE Program Review, May 2006) 2 nd Generation Leptoquarks 23

DØ Physics Summary u 41 Publications (accepted + submitted) v 2004: 2 2005: 29 2006: 10 (so far) u ~60 new results presented in Summer ’ 05 and Winter ‘ 06 u 1 fb-1 analyses are reaching results (12 at Winter ‘ 06). 8 are World’s first or best. Many more for summer! u DØ collaborators and Fermilab group members speak at all major HEP conferences u See http: //www-d 0. fnal. gov/Run 2 Physics/WWW/results. htm for complete list of released results A. Lyon (DOE Program Review, May 2006) 24

Summary u Fermilab group is deeply involved in DØ Physics u Recently (last 12 months) accepted or submitted: • • • Measurement of semileptonic branching fractions of B mesons to narrow D** states (PRL) First direct two-sided bound on the B s 0 oscillation frequency (PRL) Search for the rare decay B s 0 + - (PRL) WZ production and anomalous coupling limits (PRL) Measurement of B(t→Wb)/B(t→Wq) (PRL) Measurement of ttbar cross section using l+jets events with lifetime b-tagging (PLB) v Large role in DØ operations, Computing & software, Detector Building u Fermilab group serves DØ well by managing collaboration groups u Dmitri Denisov of Fermilab group recently elected spokesperson! Expected publications within next 12 months: • • Top quark mass in lepton+jets final state (Ideogram and Matrix Element methods) Search for the Standard Model Higgs boson in the ZH bb Channel Search for quark-lepton compositeness in dileptons Inclusive jet cross section (1 fb -1) Bs mixing in semileptonic Bs decays using the Ds decay mode (1 fb-1) Bd mixing measurement using opposite-side flavor tagging (1 fb-1) W anomalous couplings and radiation zero Measurement of WW anomalous couplings A. Lyon (DOE Program Review, May 2006) Fermiab group is deeply involved in supporting DØ 25

BACKUP SLIDES A. Lyon (DOE Program Review, May 2006) 26

Basic Techniques u Observe final decay products v v u Electrons, muons Jets (b jets) Photons Missing Transverse Energy Determine efficiencies and acceptances v From data if possible v Parameterized MC v Detailed MC u Use well understood objects to study/optimize detection and tune MC v Z decays for higher energy v J/ for lower energy A. Lyon (DOE Program Review, May 2006) Jet Energy Resolution 27