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Charm and beauty production at the Tevatron Tara Shears University of Liverpool On behalf of the CDF and D0 collaborations 248, 725, 730.

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Presentation on theme: "Charm and beauty production at the Tevatron Tara Shears University of Liverpool On behalf of the CDF and D0 collaborations 248, 725, 730."— Presentation transcript:

1 Charm and beauty production at the Tevatron Tara Shears University of Liverpool On behalf of the CDF and D0 collaborations 248, 725, 730

2 Tevatron p p collisions at s = 1.96 TeV CDFD0 _

3 Historical context: Run 1 Nason, Cacciari UPRF CDF Preliminary: (D*) Cacciari: hep-ph/ (B+): Phys Rev D B C Discrepancy from Run 1: B: (data)/ (improved theory) ~ 1.7 C: similar effects seen Aim: test predictions at Run 2

4 Tests of b and c production in Run 2 Inclusive b and c production: –Charm Phys. Rev. Lett (2003) –Beauty Phys. Rev. D (2005) –Combined c/b + X: –b + b –c,b + –b + Z Phys. Rev. Lett (2005) –b +W Phys. Rev. Lett (2005) _

5 4 analyses presented: 1.Muon tagged jet production 2.Inclusive b production 3.bb production 4.Photon + heavy flavour production Tests of b and c production at Run 2 charm beauty Direct and combined measurements _

6 tagged jet production Require events with at least 1 jet, | | 5 GeV) Jet Et 90 – 400 GeV considered 294 pb -1 data analysed Extract heavy flavour component from simulation Measurement sensitive to b + c production Pythia MC

7 tagged jet production Results consistent with LO (Pythia CTEQ 6L) and NLO (NLOJET++ CTEQ6M) NLOJET++: Z. Nagy, Phys. Rev. Lett (2002); Phys. Rev. D (2003)

8 Inclusive b production Require 1 jet, | |<0.7, with separated secondary vertex Jet Et 38 – 400 GeV 300 pb -1 data analysed Determine b fraction by fit to secondary vertex mass Results compared to LO (no NLO yet) : ratio ~1.4 as expected

9 bb production Require 2 jets, | |<1.2, both with separated secondary vertex Et 1 > 30 GeV, Et 2 > 20 GeV 64.5 pb -1 data analysed Determine b fraction by fit to secondary vertex mass Calculate cross-section as fn. of : Jet Et, m(bb), (b jets) _ _

10 bb production Results consistent with LO (Pythia CTEQ5L) and NLO + JIMMY U.E. simulation) Note: selection enhances flavour creation (LO) bb)(| | 30GeV, Et 2 >20GeV) = 34.5 ± 1.8 ± 10.5 nb LO: 38.7 ± 0.6 nb NLO: 35.7 ± 2.0 nb _

11 bb production Results consistent with LO (Pythia CTEQ5L) and NLO + JIMMY U.E. simulation) _

12 + b / + c production Sec. Vertex mass (GeV) Et > 25 GeV (| |<1.0) + jet with secondary vertex Determine b, c, uds contributions (fit secondary vertex mass) Subtract bkg, find cross- section as fn. Et 25–29 GeV 29–34 GeV 34–42 GeV 42–60 GeV

13 + b / + c production Results consistent with LO ( +b) ( +c)

14 ( + c) / ( + b) Ratio consistent with LO

15 Charm, beauty production well understood theoretically at Tevatron in Run 2 –Many analyses published (inclusive b, inclusive c, W+bb, Z+b) Shown here: –Inclusive analysis in agreement with LO, NLO –Inclusive b ratio to LO as expected (NLO comparisons forthcoming) –bb production in agreement with LO, NLO – + b, + c in agreement with LO (4x stats. forthcoming) Conclusions _ _

16 Backup slides

17 b,c Tevatron Gluon splitting Flavour excitation Flavour creation

18 How to isolate b,c experimentally Large cross-section Isolate by triggering on: –Decays to J/ –Semileptonic decays –Displaced tracks (SVT) s (TeV) mb 1 b 1nb 1pb SppS Tevatron LHC (ppX) (-) (bb)

19 Inclusive systematics QuantityUncertainty (%) Efficiency± 13.0 Luminosity± 6.5 Heavy flavour fraction± 20.0 Jet Correction ± 20.0 (P t =100) (P t =400) Unfolding ansatz± 5.0 Total ± 32.2 (100) (400)

20 Inclusive b systematics

21 Inclusive (bb) systematics QuantityUncertainty /nb Luminosity± 2.1 B tagging efficiency± 5.5 B fraction± 1.0 Acceptance (trigger efficency, jet corrections, pdfs) ± 7.0 Total± 10.5

22 + b / + c production Dominates for c Diagrams equal for b LO + (estimates from Madgraph)

23 Systematic errors: (b ) Systematic error (pb) 25 – 29 GeV 29 – 34 GeV 34 – 42 GeV 42 – 60 GeV Tag efficiency +1.7 – – – –0.9 Photon id ± 0.2± 0.1< 0.1± 0.1 Jet correction ± 0.5 ± 0.1 Jet energy scale +3.3 – – – –0.4 B jet correction ± 0.2± 0.3± 0.1 CPR fake estimate - 0.1< 0.1 trigger +2.5 –1.7< 0.1 PDF ± 0.3± 0.5± 0.2 luminosity +0.7 – – – –0.4 Final value – –

24 Systematic errors: (c ) Systematic error (pb) 25 – 29 GeV 29 – 34 GeV 34 – 42 GeV 42 – 60 GeV Tag efficiency – – – –6.4 Photon id ± 2.2± 0.4± 0.3± 0.4 Jet correction +7.9 – – Jet energy scale – – – –2.3 CPR fake estimate trigger –25.3< 0.1 PDF ± 2.2± 0.7± 0.3± 0.2 luminosity +9.6 – – – –2.7 Final value – – –30.9

25 Systematic errors: (c )/ (b ) Systematic error (pb) 25 – 29 GeV 29 – 34 GeV 34 – 42 GeV 42 – 60 GeV B tag efficiency C tag efficiency +2.4 – – – –0.8 B jet correction ± 0.2± 0.1 CPR fake estimate + 0.1< < 0.1 Final value – – –4.1


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