Inclusive b-quark and upsilon production in D Ø

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Inclusive b-quark and upsilon production in D Ø. Horst D. Wahl Florida State University DIS 2005, Madison. Outline. Tevatron and D Ø detector Bottomonium ϒ (1S) production High p t μ -tagged jet production conclusion. Tevatron – data taking. - PowerPoint PPT Presentation

Transcript of Inclusive b-quark and upsilon production in D Ø

  • Inclusive b-quark and upsilon production in DHorst D. WahlFlorida State University

    DIS 2005,Madison

  • OutlineTevatron and D detectorBottomonium (1S) productionHigh pt -tagged jet productionconclusion

  • Tevatron data takingpeak luminosity in 2005 above 1032 cm-2 s-1D collected > 690 pb-1Results shown use 150 - 300pb-1

  • Leading orderFlavor creationNext to leading orderFlavor excitationGluon splitting

  • Recent developmentsBeyond NLO: resummation of log(pt/m) terms FONLLChanges in extraction of fragmentation function from LEP dataNew PDFsImproved treatment of experimental inputs (use b-jets and b-hadrons instead of b-quarks)

  • Open Heavy Flavor ProductionLong-standing discrepancies between predicted and measured cross sections now resolved; e.g. Cacciari, Frixione, Mangano, Nason, Ridolfi,JHEP 0407 (2004) 033 combined effects ofbetter calculations (Fixed order (NLO)+ NLL= FONLL)relationship/difference between e+eand hadron collidersdifferent moments of FF relevantbetter estimate of theory errors (upward!) new appreciation of issues withquark-level measurementsTotal Cross sections (from CDF):inclusive b cross section: |y
  • Comments: Tevatron as HF FactoryThe cross sections given on the previous slide implycentral (|y|
  • The D DetectorMuon ToroidCalorimeterSolenoid, Tracking System (CFT, SMT)

  • D tracking systemForwardPreshower detectorSilicon TrackerFiber TrackerSolenoidCentral Preshower detector125 cm50cm20cmh=3 h=1.6

  • D - Muon detectorsToroid magnet (1.9 T central, 2.0 T forward)Scintillation counters PDTs (central) MDTs (forward)

  • Bottomonium productionTheory modeling of productionQuarkonium production is window on boundary region between perturbative and non-perturbative QCDfactorized QCD calculations to O(3) (currently employed by Pythia)color-singlet, color-evaporation, color-octet modelsRecent calculations by Berger et al. combining separate perturbative approaches for low and high-pt regionsPredict shape of pt distributionAbsolute cross section not predicted(1S) Production @ Tevatron:50% produced promptly, i.e. at primary vertex 50% from decay of higher mass states (e.g. b (1S) )Event selection- luminosity: 159.1 10.3 pb-1 - di-muon: pT>3, tight Tracking and Calorimeter isolation cut- invariant mass in 7 13 GeV

  • Why measure (1S) production at DBecause we can: The (1S) cross-section had been measured at the Tevatron (Run I measurement by CDF) up to a rapidity of 0.4. D has now measured this cross-section up to a rapidity of 1.8 at s = 1.96 TeV

    Measuring the (1S) production cross-section provides an ideal testing ground for our understanding of the production mechanisms of heavy quarks. There is considerable interest from theorists in these kinds of measurements: E.L. Berger, J.Qiu, Y.Wang, Phys Rev D 71 034007 (2005) and hep-ph/0411026;V.A. Khoze , A.D. Martin, M.G. Ryskin, W.J. Stirling, hep-ph/0410020

  • The AnalysisGoal: Measuring the (1S) cross-section in the channel (1S) +- as a function of pt in three rapidity ranges: 0 < | y| < 0.6, 0.6 < | y | < 1.2 and 1.2 < | y | < 1.8Sample selectionOpposite sign muons Muon have hits in all three layers of the muon system Muons are matched to a track in the central tracking system pt () > 3 GeV and | ()| < 2.2 At least one isolated Track from central tracking system must have at least one hit in the Silicon Tracker

  • Efficiencies,Cross section:

    L Luminosity kdimu local muon reconstructiony rapidity ktrk trackingacc Acceptance kqual track quality cuts trig Trigger 0.0 < y < 0.6 0.6 < y < 1.2 1.2 < y < 1.8acc 0.15 - 0.26 0.19 0.28 0.20 - 0.27 trig 0.70 0.73 0.82kdimu 0.85 0.88 0.95ktrk 0.99 0.99 0.95 kqual 0.85 0.85 0.93

  • Data vs Monte CarloTo determine our efficiencies, we only need an agreement between Monte Carlo and data within a given pT() and y() bin and not an agreement over the whole pT() and y() range at once MC Data* pt() in GeV 0 5 10 15 20 -2 -1 0 1 2 0 3 6()()0.6 < | y| < 1.2*9.0 GeV < m() < 9.8 GeV .

  • Fitting the SignalSignal: 3 states ((1S), (2S), (3S)), described by Gaussians with masses mi, widths (resolution) i, weights ci ,(i=1,2,3)Masses mi= m1+ m i1(PDG), widths i = 1 (mi/m1), for i=2,3free parameters in signal fit: m1, 1, c1, c2, c3Background: 3rd order polynomial

    All plots: 3 GeV < pt() < 4 GeVm() = 9.423 0.008 GeVm() = 9.415 0.009 GeVm() = 9.403 0.013 GeV0 < |y | < 0.60.6 < |y | < 1.21.2 < |y | < 1.8PDG: m((1S)) = 9.46 GeV

  • Results: d((1S))/dy B((1S) +-)0.0 < y < 0.6 732 19 (stat) 73 (syst) 48 (lum) pb 0.6 < y < 1.2 762 20 (stat) 76 (syst) 50 (lum) pb1.2 < y < 1.8 600 19 (stat) 56 (syst) 39 (lum) pb0.0 < y < 1.8 695 14 (stat) 68 (syst) 45 (lum) pbCDF Run I: 0.0 < y < 0.4 680 15 (stat) 18 (syst) 26 (lum) pb Fro central y bin, expect factor 1.11 increase in cross section from 1.8TeV to 1.96 TeV (Pythia)

  • Comparison with previous results(1.2 < y < 1.8)/(0.0 < y < 0.6)Pythia

  • Effects of polarizationCDF measured (1S) polarization for |y| < 0.4. How can we be sure that our forward (1S) are not significantly polarized ? So far there is no indication for (1S) polarization.CDF measured = -0.12 0.22 for pT ()> 8 GeV = 1 (-1) 100% transverse (longitudinal) polarizationThe vast majority of our (1S) has pT() < 8 GeVTheory predicts that if there is polarization it will be at large pT.

    No evidence for polarization in our signal (|y| < 1.8); ---- not enough data for a fit in the forward region alone.

    estimated the effect of (1S) polarization on our cross-section: Even at = 0.3 the cross-section changes by 15% or less in all pT bins. same effect in all rapidity regions.

  • Question: Why is CDF's systematic error so much smaller than ours ?

    Better tracking resolution --- CDF can separate the three resonances: Variations in the fit contribute considerable both to our statistical and systematic error. We believe we have achieved the best resolution currently feasible without killing the signal

    Poor understanding of our Monte-Carlo and the resulting large number of correction factors.

    Signal is right on the trigger turn-on curve.

  • Conclusions(1S) cross-section Presented measurement of (1S) cross section BR() for 3 different rapidity bins out to y() = 1.8, as a function of pt()First measurement of (1S) cross-section at s = 1.96 TeV.Shapes of d/dpt show very little dependence on rapidity.Normalized d/dpt is in good agreement with published results (CDF at 1.8TeV)-tagged jet cross section:Measured d/dpt in central rapidity region |y|
  • MotivationUnder hypothesis of compositeness, deviation from point-like behavior would likely manifest in third generation.

    Conclusion: g bb may exhibit desired deviant behavior.

    Explore b quark dijet mass as a possible signature.

    Problem~100:1 QCD:bb Solutionsm tagging2nd VTX taggingImpact parameterFit to CDFqQCD calculationCDF: PRL 82 (1999) 2038Fact: The multi-generational structure of the quark doublets requires explanation and could herald compositeness.

  • m-tagged Jet Cross-sectionGiven the simplicity of the calculation, there are few likely sources of the excess seen in p13. These could conceivably be Nm JES (central value)Resolution (i.e. smearing)eT Trigger EffePV Primary Vertex Effej Jet Effem m Efffbm Frac b m (Pt > 4 GeV)fBm Frac B m (Pt > 4 GeV)L LuminosityDpt Pt bin widthsHF HF cross-sectionsbg background cross-sectionJet + m (Pt > 5 GeV)Correlatedp13

  • p14 Analysis SummaryInclusive m-tagged jetcorrJCCB (0.5 cone jets) Standard Jet quality cuts, Standard JET TriggersJet tagged with MEDIUM muon(more on this later)DR(m, jet) < 0.5|yjet| < 0.5JES 5.3Long term goal was b-jet xsec. Difficult due to no data-driven determination of b-fraction.

  • p14 SkimmingStart with CSG QCD skimTurn into TMBTrees (40M eventson disk)Skim on TreesRemove bad runs (CAL, MET, SMT, CFT, JET, Muon)Remove events w/o 2 jetsUse Ariel d0root_ based packageSKIM 1: 1 leading jet has ~ MEDIUM m (P(m) > 4 GeV)SKIM 2: 1 leading jet has ~ loose SVT

  • p14 All Data: CSG SkimsBad runs & lumblk removed in luminosity. Only bad run removed in event counts for skims. Up until Run 193780 (07-JUN), V12.37.

    Summary 16-Aug-04

    Pre Nov 03Post Nov 03

    Analyzed40,460,04316,301,24224,158,801

    1 2vtx1,538,291646,047892,244

    1 mu405,671171,107234,564

    LuminosityBad Run Removed

    JT 251.761.020.74

    JT 4528.3121.037.28

    JT 65141.0585.7055.35

    JT 95288.61143.14145.47

    JT 125289.61143.14146.47

  • Trigger Turn OnJet TriggerCollinear muon|yjet| < 0.5Luminosity weightedStatistics uncorrelated poisson(wrong, of course)JES corrected (5.3)

  • Efficiencies.[0.37 0.05]

    EfficiencyDetailValueeTTrigger Eff1.000ePVPrimary Vertex: |z| < 50cm, 5tracks0.84 0.005emm Eff (geom, det., tracking, match)0.37 0.05ejJet Eff (jet quality cuts)0.99 0.01fbgmFrac background m (Pt > 4 GeV)Pt dependentfHFmFrac heavy flavor m (Pt > 4 GeV)Pt dependent

  • m JES DefinitionsRequired identically 2 jetsPt(jet 3, uncor) < 8 OR third jet doesnt pass jet QCOne jet contains muon, the other doesnt.| Df | > 2.84Imbalance variable:

    Independent variable:

  • Jet energy scale for -tagged jets-tagged jets also have neutrinos offset -- correction neededImbalance in events with 2 jets (one with, one without ) find 3.8% offset, not strongly pt dependent for pt in (75, 250GeV)Scale energies of -tagged jets by factor 1.038Order-randomized imbalance used to get resolution

    STD JES 5.3 gives a 3.8% offset for m-tagged jets.

    It is independent of Pt (75-250 GeV). Maybe higher above that. Need to rebin and revisit the idea that the muon Pt may be mis-measured.

    Same plot when scaling the m-tagged jet energies by 3.8%.

  • Energy Resolution

  • resolutionNeutrinos in -tagged jet resolution worse than for jets without take rms of order randomized imbalance Parameterize, Fit (fig. (a))Subtract (in quadrature) resolution for jets without obtain resolution for -tagged jets (fig. (b)Fit:

    N = 7.7 4.1S = 1.9 0.1C = 0.0 0.1Resolution parameterization used in unsmearing

  • Fitting Functions

    VariableValueErrorN17.620.32k116.901.26N23.280.60k236.333.23

    VariableValueErrorN9.56 1071.7 106a3.1950.004b5.610.04

  • Extraction of Correction Factorsexponentialnormal

  • Point by Point Unsmearing FactorsExponentialnormalUnsmearing Error small~5% for Pt > 100 GeV

    Chart2

    -11.78218618311.782186183

    -7.2372414287.237241428

    -2.71178333642.7117833364

    0.7393393083-0.7393393083

    2.8161494828-2.8161494828

    3.7697773738-3.7697773738

    3.8905285353-3.8905285353

    3.3143778523-3.3143778523

    2.3633860338-2.3633860338

    1.2157808956-1.2157808956

    -0.01262065850.0126206585

    -1.15963906611.1596390661

    -1.93440129111.9344012911

    -2.65539313982.6553931398

    -3.55344152213.5534415221

    -3.46589229283.4658922928

    -3.07840391553.0784039155

    1.6629450895-1.6629450895

    1.0462522308-1.0462522308

    Jet Pt (GeV)

    % Deviance

    Unsmearing Error

    Sheet1

    BinMeanabgexpRatio

    90-10094.64910.6090890.680853111.8-11.811.8

    100-110104.6480.5947570.637801107.2-7.27.2

    110-120114.7940.6021130.618441102.7-2.72.7

    120-130124.8540.6194720.61489299.30.7-0.7

    130-140134.6110.6443550.62620997.22.8-2.8

    140-150144.4390.6645220.63947196.23.8-3.8

    150-160154.6640.6715540.64542796.13.9-3.9

    160-170164.1840.694610.67158896.73.3-3.3

    170-180174.7750.6885460.67227397.62.4-2.4

    180-190184.4160.7049790.69640898.81.2-1.2

    190-200194.6680.7051930.705282100.0-0.00.0

    200-210204.8580.7061680.714357101.2-1.21.2

    210-220213.8970.7336120.747803101.9-1.91.9

    220-230223.9090.7370660.756638102.7-2.72.7

    230-250239.6710.71480.7402103.6-3.63.6

    250-270257.8630.7610450.787422103.5-3.53.5

    270-330294.8610.7469780.769973103.1-3.13.1

    330-400364.7180.6417530.63108198.31.7-1.7

    400-500416.2041.34481.3307399.01.0-1.0

    Sheet1

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    Jet Pt (GeV)

    % Deviance

    Unsmearing Error

    a

    90-10094.6491581.0218.08932.3752413.32335.7753*********9.070970.68085312.31611.61719111.782186183

    100-110104.648552218.362060.3559138.61532-2.93961*********5.494860.6378015.333330.227002107.237241428

    110-120114.794363215.498970.2886215.4311.25146*********3.358760.6184413.400790.178495102.7117833364

    120-130124.854236213.575090.2327183.415454.67393*********2.100130.6148922.198290.14309699.2606606917

    130-140134.61157285.72.123290.08877912.16774-2.05082*********1.357460.6262091.329620.055594397.1838505172

    140-150144.43935785.71.32520.0701371.39533-5.02638*********0.8922750.6394710.8474260.044850696.2302226262

    150-160154.66427585.71.020810.06155730.91275511.8385*********0.5891170.6454270.6588590.039730796.1094714647

    160-170164.18416585.70.6124870.0476820.6073550.845018*********0.4078920.6715880.4113390.032022796.6856221477

    170-180174.77511485.70.4231730.03963380.4111912.9139*********0.2764330.6722730.2844880.026644797.6366139662

    180-190184.4168585.70.3155240.03422330.28313211.4405*********0.1971750.6964080.2197330.023833498.7842191044

    190-200194.66880143.10.1778460.01988380.198092-10.2205*********0.1397110.7052820.1254320.0140237100.0126206585

    200-210204.85856143.10.1244920.0166360.14063-11.4755*********0.100460.7143570.08893190.011884101.1596390661

    210-220213.89743143.10.09559220.01457770.101136-5.48162*********0.07562990.7478030.07148420.0109012101.9344012911

    220-230223.90932143.10.07113840.01257560.0735494-3.27812*********0.05565030.7566380.0538260.00951518102.6553931398

    230-250239.67154143.10.0600230.00816810.046969127.7925*********0.03476650.74020.0444290.00604602103.5534415221

    250-270257.86320143.10.02223070.004970950.0259965-14.4855*********0.02047020.7874220.0175050.00391423103.4658922928

    270-330294.86129143.10.01074490.001995270.0092729815.8728*********0.007139950.7699730.008273260.00153631103.0784039155

    330-400364.7184143.10.001270330.0006351640.00159775-20.4925*********0.001008310.6310810.000801680.0004008498.3370549105

    400-500416.2041143.10.0002223070.0002223070.00018015923.3953*********0.0002397431.330730.0002958310.00029583198.9537477692

    90-10094.6491581.0218.08932.3752414.105828.2404*********8.591670.60908911.0181.44673

    100-110104.648552218.362060.3559138.77001-4.65158*********5.216020.5947574.97340.211682

    110-120114.794363215.498970.2886215.379372.22317*********3.238990.6021133.3110.173782

    120-130124.854236213.575090.2327183.341836.97976*********2.070170.6194722.214660.144162

    130-140134.61157285.72.123290.08877912.122990.0138145*********1.367960.6443551.368150.0572053

    140-150144.43935785.71.32520.0701371.3795-3.9363*********0.9167080.6645220.8806240.0466076

    150-160154.66427585.71.020810.06155730.91436311.6419*********0.6140440.6715540.685530.041339

    160-170164.18416585.70.6124870.0476820.616442-0.641585*********0.4281870.694610.425440.0331204

    170-180174.77511485.70.4231730.03963380.4217040.348209*********0.2903630.6885460.2913740.0272897

    180-190184.4168585.70.3155240.03422330.292177.99322*********0.2059740.7049790.2224380.0241267

    190-200194.66880143.10.1778460.01988380.204692-13.1152*********0.1443470.7051930.1254160.0140219

    200-210204.85856143.10.1244920.0166360.144827-14.0406*********0.1022720.7061680.08791240.0117478

    210-220213.89743143.10.09559220.01457770.103376-7.52948*********0.07583780.7336120.07012760.0106944

    220-230223.90932143.10.07113840.01257560.074374-4.3505*********0.05481860.7370660.05243370.00926906

    230-250239.67154143.10.0600230.00816810.04659828.8102*********0.03330830.71480.04290450.00583856

    250-270257.86320143.10.02223070.004970950.0250523-11.2626*********0.01906590.7610450.01691860.00378311

    270-330294.86129143.10.01074490.001995270.0086017424.9149*********0.006425320.7469780.008026180.00149042

    330-400364.7184143.10.001270330.0006351640.00146182-13.0997*********0.0009381280.6417530.0008152370.000407618

    400-500416.2041143.10.0002223070.0002223070.00018278321.6235*********0.0002458071.34480.0002989590.000298959

  • HF fraction of -tagged jet sampleSample of jets with -tagged jets contains jets with from non-HF sources (e.g. , K decays)Use Pythia with standard D detector simulation to find HF fraction of jets tagged with muons vs (true) pt

    Fit with A + B e-Pt/CA = plateau,B = zeroC = turnon

  • Pythia using standard D MC.NLO uses NLO++ (CTEQ6L)From Pythia, find fraction of jets tagged with muons (HF only).Multiply NLO cross-section by Pythia muon-fraction.This is effectively the NLO k factor.

  • ConcD Note and Conference note to EB025Residual small bug in code (should have only a few percent effect).

    JES error must be reduced to use this before setting limits on new physics.

    Just as a reminder: We are the ones with the good muon system and the new tracker.