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The “Underlying Event” CDF-LHC Comparisons

The “Underlying Event” CDF-LHC Comparisons. Outline of Talk. Jet Production: The “underlying event” in high p T jet production in Run 2 at CDF. P T (Z-boson): Tuning to fit the P T (Z) distribution in Run 2 at CDF. Great process to study the “underlying event”!.

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The “Underlying Event” CDF-LHC Comparisons

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  1. The “Underlying Event”CDF-LHC Comparisons Outline of Talk • Jet Production: The “underlying event” in high pT jet production in Run 2 at CDF. • PT(Z-boson): Tuning to fit the PT(Z) distribution in Run 2 at CDF. Great process to study the “underlying event”! • Drell-Yan: The “underlying event” in Drell-Yan production in Run 2 at CDF. • Extrapolations to the LHC: The “underlying event” in high pT jet production and Drell-Yan at CMS. Rick Field - Florida/CMS/CDF

  2. The “Transverse” Regionas defined by the Leading Jet Look at the charged particle density and the ETsum density in the “transverse” region! “Transverse” region is very sensitive to the “underlying event”! Charged Particles(pT > 0.5 GeV/c, |h| < 1) Calorimeter Towers (ET > 0.1 GeV, |h| < 1) • Look at the “transverse” region as defined by the leading calorimeter jet (MidPoint, R = 0.7, fmerge = 0.75, |h| < 2). • Define |Df| < 60o as “Toward”, 60o < -Df < 120o and 60o < Df < 120o as “Transverse 1” and “Transverse 2”, and |Df| > 120o as “Away”. Each of the two “transverse” regions have area DhDf = 2x60o = 4p/6. The overall “transverse” region is the sum of the two transverse regions (DhDf = 2x120o = 4p/3). • Study the charged particles (pT > 0.5 GeV/c, |h| < 1) and form the charged particle density, dNchg/dhdf, and the charged scalar pT sum density, dPTsum/dhdf, by dividing by the area in h-f space. • Study the calorimeter towers (ET > 0.1 GeV, |h| < 1) and form the scalar ET sum density, dETsum/dhdf. Rick Field - Florida/CMS/CDF

  3. The “Transverse” Regionas defined by the Leading Jet Look at the charged particle density and the ETsum density in the “transverse” region! “Transverse” region recieves contributions from initial & final-state radiation! Charged Particles(pT > 0.5 GeV/c, |h| < 1) Calorimeter Towers (ET > 0.1 GeV, |h| < 1) • Look at the “transverse” region as defined by the leading calorimeter jet (MidPoint, R = 0.7, fmerge = 0.75, |h| < 2). • Define |Df| < 60o as “Toward”, 60o < -Df < 120o and 60o < Df < 120o as “Transverse 1” and “Transverse 2”, and |Df| > 120o as “Away”. Each of the two “transverse” regions have area DhDf = 2x60o = 4p/6. The overall “transverse” region is the sum of the two transverse regions (DhDf = 2x120o = 4p/3). • Study the charged particles (pT > 0.5 GeV/c, |h| < 1) and form the charged particle density, dNchg/dhdf, and the charged scalar pT sum density, dPTsum/dhdf, by dividing by the area in h-f space. • Study the calorimeter towers (ET > 0.1 GeV, |h| < 1) and form the scalar ET sum density, dETsum/dhdf. Rick Field - Florida/CMS/CDF

  4. The “Underlying Event” inHigh PT Jet Production (CDF) The “Underlying Event” in High PT Jet Production HERWIG (without MPI) lies below the data for PT(jet#1) < 200 GeV/c! “Transverse” <Densities> vs PT(jet#1) Rick Field - Florida/CMS/CDF

  5. The “Central” Regionin Drell-Yan Production Look at the charged particle density and the ETsum density in the “central” region! Charged Particles(pT > 0.5 GeV/c, |h| < 1) Calorimeter Towers (ET > 0.1 GeV, |h| < 1) • Look at the “central” region after removing the lepton-pair. • Study the charged particles (pT > 0.5 GeV/c, |h| < 1) and form the charged particle density, dNchg/dhdf, and the charged scalar pT sum density, dPTsum/dhdf, by dividing by the area in h-f space. • Study the calorimeter towers (ET > 0.1 GeV, |h| < 1) and form the scalar ET sum density, dETsum/dhdf. After removing the lepton-pair everything else is the “underlying event”! Rick Field - Florida/CMS/CDF

  6. CDF Run 1 PT(Z) PYTHIA 6.2 CTEQ5L • Shows the Run 1 Z-boson pT distribution (<pT(Z)> ≈ 11.5 GeV/c) compared with PYTHIA Tune A (<pT(Z)> = 9.7 GeV/c), Tune A25 (<pT(Z)> = 10.1 GeV/c), and Tune A50 (<pT(Z)> = 11.2 GeV/c). UE Parameters ISR Parameter Intrensic KT Rick Field - Florida/CMS/CDF

  7. CDF Run 1 PT(Z) PYTHIA 6.2 CTEQ5L • Shows the Run 1 Z-boson pT distribution (<pT(Z)> ≈ 11.5 GeV/c) compared with PYTHIA Tune AW (<pT(Z)> = 11.7 GeV/c). UE Parameters ISR Parameters Effective Q cut-off, below which space-like showers are not evolved. The Q2 = kT2 in as for space-like showers is scaled by PARP(64)! Intrensic KT Rick Field - Florida/CMS/CDF

  8. Drell-Yan Productionat CDF <PT(pair)> versus M(pair) • Shows the lepton-pair average PT versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and PYTHIA Tune A. Lepton-Pair Transverse Momentum Z Z • Shows the lepton-pair average PT versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG. Rick Field - Florida/CMS/CDF

  9. Drell-Yan Productionat CMS <PT(pair)> versus M(pair) • Shows the lepton-pair average PT versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG. Lepton-Pair Transverse Momentum The lepton-pair <PT> much larger at the LHC! Z Z • Shows the lepton-pair average PT versus the lepton-pair invariant mass at 14 TeV for PYTHIA Tune AW and HERWIG. Rick Field - Florida/CMS/CDF

  10. Drell-Yan Productionat CMS <(PT)2(pair)> versus M(pair) • Shows the lepton-pair average (PT)2 versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG. Lepton-Pair Transverse Momentum Squared The lepton-pair <(PT)2> much larger at the LHC! Z Z • Shows the lepton-pair average (PT)2 versus the lepton-pair invariant mass at 14 TeV for PYTHIA Tune AW and HERWIG. Rick Field - Florida/CMS/CDF

  11. The “Underlying Event” inDrell-Yan Production (CDF) Charged particle density versus M(pair) • Shows the charged particle density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and PYTHIA Tune A. The “Underlying Event” HERWIG (without MPI) is much less active than PY Tune AW (with MPI)! Z Z • Shows the charged particle density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG (with no MPI). Rick Field - Florida/CMS/CDF

  12. The “Underlying Event” inDrell-Yan Production (CMS) Charged particle density versus M(pair) • Charged particle density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG (without MPI). The “Underlying Event” HERWIG (without MPI) is much less active than PY Tune AW (with MPI)! “Underlying event” much more active at the LHC! Z • Charged particle density versus the lepton-pair invariant mass at 14 TeV for PYTHIA Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  13. The “Underlying Event” inDrell-Yan Production (CDF) Charged PTsum density versus M(pair) • Shows the charged PTsum density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and PYTHIA Tune A. The “Underlying Event” HERWIG (without MPI) is much less active than PY Tune AW (with MPI)! Z • Shows the charged PTsum density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  14. The “Underlying Event” inDrell-Yan Production (CMS) Charged PTsum density versus M(pair) • Charged PTsum density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG (without MPI). The “Underlying Event” HERWIG (without MPI) is much less active than PY Tune AW (with MPI)! “Underlying event” much more active at the LHC! Z • Charged PTsum density versus the lepton-pair invariant mass at 14 TeV for PYTHIA Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  15. The “Underlying Event” inDrell-Yan Production (CMS) ETsum density versus M(pair) • ETsum density versus the lepton-pair invariant mass at 1.96 TeV for PYTHIA Tune AW and HERWIG (without MPI). The “Underlying Event” Z Z • ETsum density versus the lepton-pair invariant mass at 14 TeV for PYTHIA Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  16. The “Underlying Event”Drell-Yan vs Jets at CDF The “Underlying Event” in High PT Lepton-Pair and Jet Production Drell-Yan “Leading Jet” Rick Field - Florida/CMS/CDF

  17. The “Underlying Event” inHigh PT Jet Production (CMS) Charged particle density versus PT(jet#1) • Charged particle density in the “Transverse” region versus PT(jet#1) at 1.96 TeV for PY Tune AW and HERWIG (without MPI). The “Underlying Event” “Underlying event” much more active at the LHC! • Charged particle density in the “Transverse” region versus PT(jet#1) at 14 TeV for PY Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  18. The “Underlying Event” inHigh PT Jet Production (CMS) Charged PTsum density versus PT(jet#1) • Charged PTsum density in the “Transverse” region versus PT(jet#1) at 1.96 TeV for PY Tune AW and HERWIG (without MPI). The “Underlying Event” “Underlying event” much more active at the LHC! • Charged PTsum density in the “Transverse” region versus PT(jet#1) at 14 TeV for PY Tune AW and HERWIG (without MPI).. Rick Field - Florida/CMS/CDF

  19. The “Underlying Event” inHigh PT Jet Production (CMS) • ETsum density in the “Transverse” region versus PT(jet#1) at 1.96 TeV for PY Tune AW and HERWIG (without MPI). The “Underlying Event” ETsum density versus PT(jet#1) “Underlying event” much more active at the LHC! • ETsum density in the “Transverse” region versus PT(jet#1) at 14 TeV for PY Tune AW and HERWIG (without MPI). Rick Field - Florida/CMS/CDF

  20. The “Underlying Event”Drell-Yan vs Jets at CMS The “Underlying Event” in High PT Lepton-Pair and Jet Production Drell-Yan “Leading Jet” Rick Field - Florida/CMS/CDF

  21. UE&MB@CMS UE&MB@CMS Rick Field (Florida) Darin Acosta (Florida) Albert De Roeck (CERN) Paolo Bartalini (UF Postdoc at CERN) Livio Fano' (INFN/Perugia at CERN) Filippo Ambroglini (INFN/Perugia at CERN) Khristian Kotov (UF Student, Acosta) Me at CMS! • Measure Min-Bias and the “Underlying Event” at CMS • The plan involves two phases. • Phase 1 would be to measure min-bias and the “underlying event” as soon as possible (when the luminosity is low), perhaps during commissioning. We would then tune the QCD Monte-Carlo models for all the other CMS analyses. Phase 1 would be a service to the rest of the collaboration. As the measurements become more reliable we would re-tune the QCD Monte-Carlo models if necessary and begin Phase 2. • Phase 2 is “physics” and would include comparing the min-bias and “underlying event” measurements at the LHC with the measurements we have done (and am doing now) at CDF and then writing a physics publication. Darin Rick Field - Florida/CMS/CDF

  22. UE&MB@CMS • “Underlying Event” Studies: The “transverse region” in “leading Jet” and “back-to-back” jet production. The “central region” in Drell-Yan production. (requires charged tracks and calorimeter and muons for Drell-Yan) • Min-Bias Studies: Charged particle distributions and correlations. Construct “charged particle jets” and look at “mini-jet” structure and the onset of the “underlying event”. (requires only charged tracks) • Drell-Yan Studies: Transverse momentum distribution of the lepton-pair versus the mass of the lepton-pair, <pT(pair)>, <pT2(pair)>, ds/dpT(pair) (only requires muons). Event structure for large lepton-pair pT (i.e.mm +jets, requires muons and calorimeter). Rick Field - Florida/CMS/CDF

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