1. Rick Field – Florida/CDF/CMS
MC & Tuning at CMS
Tevatron to LHC: UE & MB
Rick Field
University of Florida
Outline of Talk
The “underlying event” in jet production at CDF.
The “underlying event” in lepton-pair production at CDF.
CERN December
Look at <pT> versus Nchg in “min-bias” and lepton-pair production at CDF.
Rick Field
Craig Group
Deepak Kar
CDF Run 2
CMS at the LHC
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

2. Tune A energy dependence!
PYTHIA 6.2 Tunes
All use LO as
with L = 192 MeV!
Parameter
Tune AW
Tune DW
Tune D6
PDF
CTEQ5L
CTEQ6L
MSTP(81) 1
MSTP(82) 4
PARP(82)
2.0 GeV
1.9 GeV
1.8 GeV
PARP(83)
0.5
PARP(84)
0.4
PARP(85)
0.9
1.0
PARP(86)
0.95
PARP(89)
1.8 TeV
PARP(90)
0.25
PARP(62)
1.25
PARP(64)
0.2
PARP(67)
4.0
2.5
MSTP(91)
PARP(91)
2.1
PARP(93)
15.0
UE Parameters
Uses CTEQ6L
Tune A energy dependence!
ISR Parameter
Intrinsic KT
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

3. ATLAS energy dependence!
PYTHIA 6.2 Tunes
All use LO as
with L = 192 MeV!
Parameter
Tune DWT
Tune D6T
ATLAS
PDF
CTEQ5L
CTEQ6L
MSTP(81) 1
MSTP(82) 4
PARP(82)
GeV
GeV
1.8 GeV
PARP(83)
0.5
PARP(84)
0.4
PARP(85)
1.0
0.33
PARP(86)
0.66
PARP(89)
1.96 TeV
1.0 TeV
PARP(90)
0.16
PARP(62)
1.25
PARP(64)
0.2
PARP(67)
2.5
MSTP(91)
PARP(91)
2.1
PARP(93)
15.0
5.0
UE Parameters
ATLAS energy dependence!
ISR Parameter
Intrinsic KT
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

4. These are “old” PYTHIA 6.2 tunes! ATLAS energy dependence!
See the talk by
Hendrik Hoeth
for “new” tunes!
All use LO as
with L = 192 MeV!
Parameter
Tune DWT
Tune D6T
ATLAS
PDF
CTEQ5L
CTEQ6L
MSTP(81) 1
MSTP(82) 4
PARP(82)
GeV
GeV
1.8 GeV
PARP(83)
0.5
PARP(84)
0.4
PARP(85)
1.0
0.33
PARP(86)
0.66
PARP(89)
1.96 TeV
1.0 TeV
PARP(90)
0.16
PARP(62)
1.25
PARP(64)
0.2
PARP(67)
2.5
MSTP(91)
PARP(91)
2.1
PARP(93)
15.0
5.0
UE Parameters
ATLAS energy dependence!
ISR Parameter
Intrinsic KT
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

5. JIMMY at CDF
JIMMY was tuned to fit the energy density in the “transverse” region for “leading jet” events!
JIMMY
Runs with HERWIG and adds multiple parton interactions!
PT(JIM)= 2.5 GeV/c.
The Energy in the “Underlying Event” in High PT Jet Production
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
PT(JIM)= 3.25 GeV/c.
“Transverse” <Densities> vs PT(jet#1)
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

6. JIMMY at CDF
JIMMY was tuned to fit the energy density in the “transverse” region for “leading jet” events!
JIMMY
Runs with HERWIG and adds multiple parton interactions!
PT(JIM)= 2.5 GeV/c.
The Energy in the “Underlying Event” in High PT Jet Production
The Drell-Yan JIMMY Tune
PTJIM = 3.6 GeV/c,
JMRAD(73) = 1.8
JMRAD(91) = 1.8
JIMMY: MPI
J. M. Butterworth
J. R. Forshaw
M. H. Seymour
PT(JIM)= 3.25 GeV/c.
“Transverse” <Densities> vs PT(jet#1)
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

7. Charged Particle Density
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

8. Charged Particle Density
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “transverse” and “away” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

9. Rick Field – Florida/CDF/CMS
Charged PTsum Density
Data at 1.96 TeV on the charged scalar PTsum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

10. Rick Field – Florida/CDF/CMS
Charged PTsum Density
Data at 1.96 TeV on the charged scalar PTsum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “transverse” and “away” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

11. The “TransMAX/MIN” Regions
Data at 1.96 TeV on the charged particle density, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of PT(Z) or the leading jet pT for the “transMAX”, and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

12. The “TransDIF” Density
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “leading jet” events as a function of the leading jet pT and for Z-Boson events as a function of PT(Z) for “TransDIF” = “transMAX” minus “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

13. The “TransMAX/MIN” Regions
Data at 1.96 TeV on the charged scalar PTsum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” and “Leading Jet” events as a function of PT(Z) or the leading jet pT for the “transMAX”, and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

14. Charged Particle <pT>
Data at 1.96 TeV on the charged particle average pT, with pT > 0.5 GeV/c and |h| < 1 for the “toward” region for “Z-Boson” and the “transverse” region for “Leading Jet” events as a function of the leading jet pT or PT(Z). The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level). The Z-Boson data are also compared with PYTHIA Tune DW, the ATLAS tune, and HERWIG (without MPI)
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

15. Z-Boson: “Towards”, Transverse”, & “TransMIN” Charge Density
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

16. Z-Boson: “Towards” & “TransMIN” Charge Density
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

17. Z-Boson: “Towards” & “TransMIN” Charge Density
Data at 1.96 TeV on the charged scalar PTsum density, dPT/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

18. Z-Boson: “Towards” Region
Data at 1.96 TeV on the density of charged particles, dN/dhdf, with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

19. Z-Boson: “Towards” Region
HW (without MPI)
almost no change!
Data at 1.96 TeV on the average pT of charged particles with pT > 0.5 GeV/c and |h| < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

20. Proton-Antiproton Collisions
stot = sEL + sSD + sDD + sHC
The “hard core” component contains both “hard” and “soft” collisions.
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

21. Min-Bias Correlations
New
Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT > 0.4 GeV/c, |h| < 1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle level and are compared with PYTHIA Tune A at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

22. Min-Bias: Average PT versus Nchg
Beam-beam remnants (i.e. soft hard core) produces low multiplicity and small <pT> with <pT> independent of the multiplicity. =
The CDF “min-bias” trigger picks up most of the “hard core” component!
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

23. Min-Bias: Average PT versus Nchg
Beam-beam remnants (i.e. soft hard core) produces low multiplicity and small <pT> with <pT> independent of the multiplicity.
Hard scattering (with no MPI) produces large multiplicity and large <pT>. = +
The CDF “min-bias” trigger picks up most of the “hard core” component!
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

24. Min-Bias: Average PT versus Nchg
Beam-beam remnants (i.e. soft hard core) produces low multiplicity and small <pT> with <pT> independent of the multiplicity.
Hard scattering (with no MPI) produces large multiplicity and large <pT>.
Hard scattering (with MPI) produces large multiplicity and medium <pT>.
This observable is sensitive to the MPI tuning! = + +
The CDF “min-bias” trigger picks up most of the “hard core” component!
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

25. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT > 0.4 GeV/c, |h| < 1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle leveland are compared with PYTHIA Tune A, Tune DW, and the ATLAS tune at the particle level (i.e. generator level).
Particle level predictions for the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, |h| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2.
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

26. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
Z-boson production (with low pT(Z) and no MPI) produces low multiplicity and small <pT>. =
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

27. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
No MPI!
Z-boson production (with low pT(Z) and no MPI) produces low multiplicity and small <pT>.
High pT Z-boson production produces large multiplicity and high <pT>. = +
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

28. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
No MPI!
Z-boson production (with low pT(Z) and no MPI) produces low multiplicity and small <pT>.
High pT Z-boson production produces large multiplicity and high <pT>.
Z-boson production (with MPI) produces large multiplicity and medium <pT>. = + +
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

29. Average PT(Z) versus Nchg
No MPI!
Predictions for the average PT(Z-Boson) versus the number of charged particles (pT > 0.5 GeV/c, |h| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2.
Data on the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, |h| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

30. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
PT(Z) < 10 GeV/c
No MPI!
Data the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, |h| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV, PT(pair) < 10 GeV/c) at CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

31. Rick Field – Florida/CDF/CMS
Average PT versus Nchg
Remarkably similar behavior! Perhaps indicating that MPI playing an important role in both processes.
Data the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, |h| < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV, PT(pair) < 10 GeV/c) at CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level (i.e. generator level).
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

32. Fermilab Today Result of the Week
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

33. CDF-QCD Data for Theory
Summary
It is important to produce a lot of plots (corrected to the particle level) so that the theorists can tune and improve the QCD Monte-Carlo models. If they improve the “transverse” region they might miss-up the “toward” region etc.. We need to show the whole story!
We are making good progress in understanding and modeling the “underlying event” in jet production and in Drell-Yan. Tune A and Tune AW describe the data very well, although not perfect. However, we do not yet have a perfect fit to all the features of the CDF “underlying event” data!
Looking at <pT> versus Nchg in Drell-Yan with 70 < Mpair) < 110 GeV and PT(pair) < 5 GeV is a good way to look at MPI and the color connections. The data show the correlations expected from MPI!
There are over 128 plots to get “blessed” and then to published. So far we have only looked at average quantities. We plan to also produce distributions and flow plots.
CDF-QCD Data for Theory
I plan to construct a “CDF-QCD Data for Theory” WEBsite with the “blessed” plots together with tables of the data points and errors so that people can have access to the results .
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS

34. Summary CDF-QCD Data for Theory
It is important to produce a lot of plots (corrected to the particle level) so that the theorists can tune and improve the QCD Monte-Carlo models. If they improve the “transverse” region they might miss-up the “toward” region etc.. We need to show the whole story!
We are making good progress in understanding and modeling the “underlying event” in jet production and in Drell-Yan. Tune A and Tune AW describe the data very well, although not perfect. However, we do not yet have a perfect fit to all the features of the CDF “underlying event” data!
CDF Run 2 publication. Should be out by the end of the year!
Looking at <pT> versus Nchg in Drell-Yan with 70 < Mpair) < 110 GeV and PT(pair) < 5 GeV is a good way to look at MPI and the color connections. The data show the correlations expected from MPI!
There are over 128 plots to get “blessed” and then to published. So far we have only looked at average quantities. We plan to also produce distributions and flow plots.
CDF-QCD Data for Theory
I plan to construct a “CDF-QCD Data for Theory” WEBsite with the “blessed” plots together with tables of the data points and errors so that people can have access to the results .
MC & Tuning at CMS December 16, 2008
Rick Field – Florida/CDF/CMS