1. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D01 b-production cross-section at the TeVatron Eric Kajfasz, CPPM/D0 kajfasz@fnal.gov for the CDF and D0 collaborations

2. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D02 The TeVatron Main Injector & Recycler Tevatron Chicago   p source Booster pp p p pp 1.96 TeV CDF DØ Run 1 1.8 TeV 0.1 fb -1 FY base (fb -1 ) stretch (fb -1 ) 051.72.5 063.25.0 07 shutdown 084.78 096.511 Run 2 1.96 TeV

3. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D03 b-jet production: Run I results D0 - 1.8TeV b B E jet ~E b  E B

4. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D04 x b-jet production: phenomenology Binnewies, Kniehl, Kramer - hep-ph/9802231 Kniehl - hep-ph/0211008 Re-determine LO and NLO B-meson Fragmentation Functions using data collected at LEP1 Cacciari, Nason - hep-ph/0204025 Nason - hep-ph/0301003 retuned FF and NLL resummations (F0NLL) Careful treatment of Fragmentation Functions helps... PRELIMINARY

5. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D05 b-jet production: phenomenology R.D. Field - hep-ph/0201112 qb q b q q b g b b g g g b flavor creation flavor exitation shower/fragmentation integrated b-quark cross-section for p T > p Tmin b g g b 3 sources CDF Pythia 6.2 (CTEQ5L) - normalized  correlations toward away LLMC estimates rather uncertain, but...

6. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D06 Run I: CDF detector

7. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D07 Run I: Secondary Vertex Correlations Uses 90 pb -1 sample taken by CDF in 1994-1995 run (Run IB) Enrich b content of data by requiring an electron or muon trigger Use tracking information to reconstruct decay vertices of both B hadrons Compare correlations of these reconstructed vertices to PYTHIA and HERWIG predictions Use Monte Carlo to convert raw secondary vertex correlations to B hadron correlations Primary Vertex Tracks Secondary Vertex

8. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D08 Run I: Secondary Vertex Correlations  = opening angle between momentum vectors of secondary vertices in the transverse plane Detector effects are simulated in Monte Carlo Relative contribution from flavor creation, flavor excitation, and gluon splitting varied to give best match to data Similar distributions for muons

9. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D09 Run I: Measured B-Hadron Correlations  = opening angle between measured B directions in transverse plane Detector effects unfolded from data using PYTHIA other corrections: o mistags o tags from prompt charm o sequential double tags Error bars show statistical errors 17,000 e+  events consistant with substantial contribution from flavor excitation+gluon splitting

10. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D010 Run II D0 detector Calorimeters Tracker Muon System Beamline Shielding Electronics protons 20 m anti-protons Solenoid Central Fiber Tracker Silicon Microstrip Tracker

11. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D011 D0 Integrated Luminosity February data taking efficiency: ~90% per run ~85% overall April 19, 2002 - March 11, 2003 Current trigger rates: L1 rate 1KHz L2 rate 0.6 KHz L3 rate 50 Hz

12. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D012 RunII b-jet cross-section Strategy: o use 3.4 pb -1 of data (1.96 TeV - 02/28/02-05/10/02) o Measure  +jet cross section o Extract b-content using P T Rel Data selection and kinematic cuts: o jet: 0.5 cone   : track measured in muon system only o |  jet | < 0.6 o |E T jet | > 20 GeV o |   | < 0.8 o p T  > 6 GeV/c   R(jet,  ) < 0.7

13. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D013 RunII:  +jet cross-section Jet reco efficiency: 100% for E > 20 GeV  reco efficiency: 43.7  0.8(stat)  2.2(syst) % Jet resolution: dijet p T imbalance  momentum resolution: from central tracks

14. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D014 T   +jet RunII: b-tagging Fit P T Rel templates in jet E T bins P T Rel for jets with 20 GeV < E T < 25 GeV signal template: from b ->  Monte-Carlo background template: from 1.5 million QCD events

15. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D015 RunII: b-jet fraction b-jet fraction as a function of jet E T # of bins constrained by statistical limitations of background templates fitted with functional form: a + b/E T jet

16. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D016 RunII: b-jet cross-section ansatz function used to unfold the calorimeter resolution dominant error from jet energy scale agreement with data similar to what was seen in Run I band covers uncertainty due to: b-quark mass renormalization/factorization scales pdf’s fragmentation functions

17. Moriond QCD March 24, 2003Eric Kajfasz, CPPM/D017 Conclusions better phenomenological understanding of heavy flavor production (sources, retuned FF, NLL resummations...) tend to make the shape and normalization of calculated distributions closer to their measured ones. There does not seem to be a need for new phenomena here... b-bbar correlation distributions indicate that at the TeVatron all three sources of b-quarks are important. We are just beginning to reap the fruits of RunII data. New results will follow soon from both CDF and D0, stay tuned...