Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ at Run IIa as the new B-Physics/charmonium player Heriberto Castilla Cinvestav-IPN Dzero Collaboration Workshop on Quarkonium November 8-10, 2002 at CERN

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Physics Challenges  The Upgraded Tevatron Interactions / xing Bunch xing (ns)  Ldt (pb -1 /week) 5.2    Typical L (cm -2 s -1 )  s (TeV) 140   366  6 Bunches in Turn Run 2bRun 2aRun 1b Run 1  Run 2a  Run 2b 0.1 fb -1  2  4 fb -1  15 fb -1 Peak Lum. achieved over 3.5  cm  2 s  1 Planned to reach Run 2a design by Spring 2003 Physics goals for Run 2  precision studies of weak bosons, top, QCD, B-physics  searches for Higgs, supersymmetry, extra dimensions, other new phenomena require  electron, muon, and tau identification  jets and missing transverse energy  flavor tagging through displaced vertices and leptons  luminosity, luminosity, luminosity…

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Tevatron Luminosity

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Calorimeters Tracker Muon System Beamline Shielding Electronics protons 20 m antiprotons The Run II DØ Detector

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ in RunII Center of Mass Energy = 1.96 TeV Expect 2 fb -1 by end of 2004 (RunIIa), 15 fb -1 by 2008 (RunIIb) Goals –B Physics ( B lifetime, B mixing, exclusive decays) –J/  and  production properties (polarization vs p T ) –Comprehensive study of top quark properties –Precise measurements of m top, m W –Search for new phenomena (SUSY, technicolor,…) –Search for the Higgs boson –QCD (proton structure, quark compositeness) DØ’s strength is high-pT Physics but we can also do low- pT Physics Requires –Measurement of leptons (e,  ), jets, missing p T –Flavor tagging of jets

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ Tracker 125 cm

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Silicon Microstrip Tracker (SMT) 4-layer barrel cross-section 6 Barrels 12 F Disks 4 H Disks

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Tracking Performance p T dependent impact parameter resolution at vertex is  100  m using SMT only tracks and improves to  48  m when CFT data is combined with SMT data-- and is expected to improve further as studies progress Ks +-Ks +- track x y

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Fully commissioned Bottom B/C Scintillators A-  Scint PDTs Forward Tracker (MDTs) Shielding Forward Trigger Scintillators Central and Forward regions, coverage up to  = ± 2 Three layers: one inside (A), two outside (B, C) the toroid magnets Consists of scintillators and drift tubes Central Proportional Drift Tubes (PDT’s) 6624 drift cells (10.1  5.5 cm) in 94 three- and four-deck chambers Central Scintillation Counters 360 “cosmic ray” counters outside the toroid (  = 22.5  ) 630 “A  ” counters inside (  = 4.5  ),  = 0.1 Forward Mini Drift Tubes (MDT’s) cell tubes in 8 octants per layer on North and South side, cell cross-section 9.4  9.4 mm Forward Scintillation Counters (Pixels) 4214 counters on the North and South side  = 4.5  matches the MDT sector size Muon System

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Muon System Muon Trigger Counters DØ Detector in Collision Hall, January 2001

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Muon Timing Cosmic rays  ’s from Collisions Timing cuts reduce cosmic bckg., could aid in detection of slow moving particles M = 3.08  0.04 GeV  = 0.78  0.08 GeV Muon stand alone systemMuon plus central tracking J/  invariant mass Matching of central tracks to  ’s improves momentum resolution CHEP02 – 31 st International Conference on High Energy Physics, Amsterdam, 24 – 31 July, 2002 Muon System Performance

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla L3/DAQ Tape 2.3 (7.5) MHz 5 kHz 1 kHz L3 Trigger 50 Hz Decision times: ~4.2  s ~100  s ~50 ms Level 1 Subdetectors Towers, tracks, clusters, E T Some correlations Pipelined Level 2 Correlations Calibrated Data Separated vertex Physics Objects e, , j, , E T Level 3 Simple Reconstruction Physics Algorithms Entire Trigger Menu configurable and downloadable at Run start Trigger Meisters provide trigger lists for the experiment by collecting trigger requests from all physics groups in the Trigger Board All past and present trigger lists are stored and maintained in the dedicated trigger database DØ Trigger System

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ Beauty/Charmonium Physics Program J/ψ cross section and polarization Y cross section B Lifetimes Average B lifetime: b  J/  X  b lifetime:  b  J/  0 B 0 s lifetime and width: B 0 s  J/  CP violation, sin(2  ): B 0  J/  K 0 s B 0 s mixing: B s  D s l X, B s  D s (n  ) Rare decays, cross sections

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla ~30% systematic uncertainty 4.8 pb -1 of data region not measured in Run I Run II J/  production cross section

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla θ = angle(J/ψ lab,μ J/ψ ) I(θ) = 3/2/(α+3) (1+ α cos 2 θ) α = (σ T -2σ L )/(σ T +2σ L ) p t (J/ψ) > 10 |η(J/ψ)| < 1.8 p t (μ) > 2 η(μ)| < 1.9 Future measurements: J/  polarization

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla    +  - in DØ p T of tracks > 2 GeV

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Average B Hadron Lifetime 416 ± 30 signal events 2184 ± 47 prompt J/  ’s  (B) = 492 ± 37  m (PDG:  (B) = 469  m) Same sample as B ±  J/  K ± p T (J/  )>4 GeV/c

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla DØ’s First B Hadron Candidates ~5 pb -1 J/  vertex –p T (track)>2 GeV/c, matched to a muon –Positive decay length p T (K)>0.5 GeV/c B vertex –p T (B)>10 GeV/c –  2 <10 –Decay length>120  m –Colinearity angle (p  l)>0.9

Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla Conclusion First physics results at 1.96 TeV –J/  studies –J/  cross section (cross checks with Run I measurement) –Average B Lifetime consistent with previous measurements –First observation in D0 of a charged B Tools to work on quarkonium –Prompt J/  (  ’) and from Bs –Upsilon –Polarization measurements –  radiative decays Improvements in store: –CTT and STT triggers soon –Increased rate of J/  and  to tape