51 st Cracow School of Theoretical Physics The Soft Side of the LHC Min-Bias and the Underlying Event at the LHC Rick Field University of Florida

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1 5 st Cracow School of Theoretical Physics The Soft Side of the LHC Min-Bias and the Underlying Event at the LHC Rick Field University of Florida Lecture : Outline Review: The CDF Tevatron underlying event tunes (Tune A, B, D, AW, DW, D6, DWT, D6T). Predicting the behavior of the underlying event at the LHC. What we expected to see. How well did we do at predicting the behavior of the underlying event at the LHC ( and )? LHC PYTHIA Tunes: PYTHIA 6.4 tunes (AMBT, Z, Z2) and PYTHIA 8 Tune C4. Proton Underlying Event Outgoing Parton Final-State Radiation UE&MB@CMS Outgoing Parton PT(hard) Initial-State Radiation Proton Underlying Event Zakopane, Poland, June -9, 20 CMS ATLAS Rick Field Florida/CDF/CMS Page

2 5 st Cracow School of Theoretical Physics The Soft Side of the LHC Min-Bias and the Underlying Event at the LHC Rick Field University of Florida Lecture 2: Tomorrow How are min-bias collisions related to the underlying event. How well did we do at predicting the behavior of minbias collisions at the LHC ( and )? Baryon and Strange Particle Production at the LHC: Fragmentation tuning. p K + K Λ short u u d u s d s + d s u d s K - u s UE&MB@CMS Ξ d s s Zakopane, Poland, June -9, 20 CMS ATLAS Rick Field Florida/CDF/CMS Page 2

3 Toward an Understanding of Hadron-Hadron Collisions From Feynman-Field to the LHC Rick Field University of Florida Lecture 3: Tuesday Evening Before Feynman-Field Phenomenology: The Berkeley years. Feynman The early days of Feynman-Field Phenomenology. From 7 GeV/c π 0 s to TeV Jets! Field Rick Field Florida/CDF/CMS Page 3

4 QCD Monte-Carlo Models: High Transverse Momentum Jets Hard Scattering Outgoing Parton Initial-State Radiation PT(hard) Hard Scattering Jet Jet Initial-State Radiation Outgoing Parton PT(hard) Hard Scattering Component Proton Underlying Event AntiProton Underlying Event Outgoing Parton Final-State Radiation Outgoing Parton Jet Final-State Radiation Proton Underlying Event AntiProton Underlying Event Underlying Event Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and finalstate gluon radiation (in the leading log approximation or modified leading log approximation). The underlying event consists of the beam-beam remnants and from particles arising from soft or semi-soft multiple parton interactions (MPI). The underlying event is an unavoidable Of course the outgoing colored partons fragment into hadron jet and inevitably underlying event background to most collider observables observables receive contributions from initial and final-state radiation. and having good understand of it leads to more precise collider measurements! Rick Field Florida/CDF/CMS Page 4

5 MPI, Pile-Up, and Overlap MPI: Multiple Parton Interactions Outgoing Parton PT(hard) Initial-State Radiation Proton Proton MPI: Additional 2-to-2 parton-parton scatterings within a single hadron-hadron collision. Underlying Event Underlying Event Outgoing Parton Final-State Radiation Pile-Up Proton Pile-Up Proton Proton Primary Proton Interaction Region z Pile-Up: More than one hadron-hadron collision in the beam crossing. Overlap Overlap: An experimental timing issue where a hadron-hadron collision from the next beam crossing gets included in the hadronhadron collision from the current beam crossing because the next crossing happened before the event could be read out. Rick Field Florida/CDF/CMS Page 5

6 Traditional Approach Transverse region very sensitive to the underlying event! CDF Run Analysis Charged Jet # Direction Toward-Side Jet φ Charged Particle φ Correlations P T > PT min η < η cut Leading Object Direction φ 2π Leading Calorimeter Jet or Leading Charged Particle Jet or Leading Charged Particle or Z-Boson Away Region Transverse Region Toward Toward φ Leading Object Transverse Transverse Transverse Transverse Toward Region Away Away Transverse Region Away-Side Jet Away Region 0 -η cut η +η cut Look at charged particle correlations in the azimuthal angle φ relative to a leading object (i.e. CaloJet#, ChgJet#, PTmax, Z-boson). For CDF PTmin = GeV/c η cut =. Define φ φ < 60 o as Toward, 60 o < φ φ < 20 o as Transverse, and φ φ > 20 o as Away. All three regions have the same area in η-φ space, η φ φ = 2η cut 20 o = 2η cut 2π/3. Construct densities by dividing by the area in η-φ space. Rick Field Florida/CDF/CMS Page 6

7 Charged Jet # Direction Transverse Toward Away φ Transverse Beam-Beam Remnants ISAJET 7.32 (without MPI) Transverse Density ISAJET uses a naïve leading-log parton shower-model which does not agree with the data! "Transverse" Charged Density CDF Run Data data uncorrected theory corrected "Remnants" Isajet February 25, PT(charged jet#) (GeV/c) "Hard".8 TeV η <.0 PT> GeV ISAJET Hard Component Plot shows average transverse charge particle density ( η <, p T > GeV) versus P T (charged jet#) compared to the QCD hard scattering predictions of ISAJET 7.32 (default parameters with P T (hard)>3 GeV/c). The predictions of ISAJET are divided into two categories: charged particles that arise from the break-up of the beam and target (beam-beam remnants); and charged particles that arise from the outgoing jet plus initial and final-state radiation (hard scattering component). Rick Field Florida/CDF/CMS Page 7

8 Charged Jet # Direction Transverse Toward Away Beam-Beam Remnants φ Transverse HERWIG 6.4 (without MPI) Transverse Density "Transverse" Charged Density HERWIG uses a modified leadinglog parton shower-model which does agrees better with the data! CDF Run Data data uncorrected theory corrected Total "Remnants" "Hard" PT(charged jet#) (GeV/c) Herwig 6.4 CTEQ5L PT(hard) > 3 GeV/c.8 TeV η <.0 PT> GeV HERWIG Hard Component Plot shows average transverse charge particle density ( η <, p T > GeV) versus P T (charged jet#) compared to the QCD hard scattering predictions of HERWIG 5.9 (default parameters with P T (hard)>3 GeV/c without MPI). The predictions of HERWIG are divided into two categories: charged particles that arise from the break-up of the beam and target (beam-beam remnants); and charged particles that arise from the outgoing jet plus initial and final-state radiation (hard scattering component). Rick Field Florida/CDF/CMS Page 8

9 Parameter Default Tuning PYTHIA 6.2: Multiple Parton Interaction Parameters Description PARP(83) PARP(84) PARP(85) Double-Gaussian: Fraction of total hadronic matter within PARP(84) Double-Gaussian: Fraction of the overall hadron radius containing the fraction PARP(83) of the total hadronic matter. Probability that the MPI produces two gluons with color connections to the nearest neighbors. Hard Core Color String Multiple Parton Interaction Color String PARP(86) 0.66 Probability that the MPI produces two gluons either as described by PARP(85) or as a closed gluon loop. The remaining fraction consists of quark-antiquark pairs. Multiple Parton Determine Interaction by comparing with 630 GeV data! Color String PARP(89) PARP(82) PARP(90) TeV.9 GeV/c 0.6 Determines the reference energy E 0. The cut-off P T0 that regulates the 2-to-2 scattering divergence /PT 4 /(PT 2 +P T0 2 ) 2 Determines the energy dependence of the cut-off P T0 as follows P T0 (E cm ) = P T0 (E cm /E 0 ) ε with ε = PARP(90) PT0 (GeV/c) PYTHIA Hard-Scattering Cut-Off PT0 Take E 0 =.8 TeV ε = 0.25 (Set A)) PARP(67).0 A scale factor that determines the maximum parton virtuality for space-like showers. The larger the value of PARP(67) the more initialstate radiation. ε = 0.6 (default) 00,000 0,000 00,000 Reference point at.8 TeV CM Energy W (GeV) Rick Field Florida/CDF/CMS Page 9

10 Parameter Default Tuning PYTHIA 6.2: Multiple Parton Interaction Parameters Description PARP(83) PARP(84) PARP(85) Double-Gaussian: Fraction of total hadronic matter within PARP(84) Double-Gaussian: Fraction of the overall hadron radius containing the fraction PARP(83) of the total hadronic matter. Determines the energy Probability that the MPI produces two gluons dependence of the MPI! with color connections to the nearest neighbors. Hard Core Color String Multiple Parton Interaction Color String PARP(86) 0.66 Probability that Affects the MPI the produces amount two of gluons either as described initial-state by PARP(85) radiation! or as a closed gluon loop. The remaining fraction consists of quark-antiquark pairs. Multiple Parton Determine Interaction by comparing with 630 GeV data! Color String PARP(89) PARP(82) PARP(90) TeV.9 GeV/c 0.6 Determines the reference energy E 0. The cut-off P T0 that regulates the 2-to-2 scattering divergence /PT 4 /(PT 2 +P T0 2 ) 2 Determines the energy dependence of the cut-off P T0 as follows P T0 (E cm ) = P T0 (E cm /E 0 ) ε with ε = PARP(90) PT0 (GeV/c) PYTHIA Hard-Scattering Cut-Off PT0 Take E 0 =.8 TeV ε = 0.25 (Set A)) PARP(67).0 A scale factor that determines the maximum parton virtuality for space-like showers. The larger the value of PARP(67) the more initialstate radiation. ε = 0.6 (default) 00,000 0,000 00,000 Reference point at.8 TeV CM Energy W (GeV) Rick Field Florida/CDF/CMS Page 0

11 PYTHIA default parameters Parameter MSTP(8) MSTP(82) PARP(8) PARP(82) PARP(89) PARP(90) PARP(67) PYTHIA Defaults MPI constant probability , , , "Transverse" Charged Density scattering CDF Data data uncorrected theory corrected Pythia (default) MSTP(82)= PARP(8) =.9 GeV/c PT(charged jet#) (GeV/c).8 TeV η <.0 PT> GeV CTEQ3L CTEQ4L CTEQ5L CDF Min-Bias CDF JET20 Plot shows the Transverse charged particle density versus P T (chgjet#) compared to the QCD hard scattering predictions of PYTHIA (P T (hard) > 0) using the default parameters for multiple parton interactions and CTEQ3L, CTEQ4L, and CTEQ5L. Note Change PARP(67) = 4.0 (< 6.38) PARP(67) =.0 (> 6.38) Default parameters give very poor description of the underlying event! Rick Field Florida/CDF/CMS Page

12 PYTHIA CTEQ5L Parameter MSTP(8) MSTP(82) PARP(82) PARP(83) PARP(84) PARP(85) PARP(86) PARP(89) PARP(90) PARP(67) Tune B.0.8 TeV New PYTHIA default (less initial-state radiation) 4.9 GeV.0 Run PYTHIA Tune A Tune A GeV TeV CDF Default Feburary 25, 2000! "Transverse" Charged Density CDF Preliminary data uncorrected theory corrected CTEQ5L Plot shows the transverse charged particle density versus P T (chgjet#) compared to the QCD hard scattering predictions of two tuned versions of PYTHIA (CTEQ5L, Set B (PARP(67)=) and Set A (PARP(67)=4)). Old PYTHIA default (more initial-state radiation) PYTHIA (Set B) PARP(67)= PYTHIA (Set A) PARP(67)= PT(charged jet#) (GeV/c) Run Analysis.8 TeV η <.0 PT> GeV Rick Field Florida/CDF/CMS Page 2

13 Transverse Cones vs Transverse Regions φ 2π Away Region Transverse Region Leading Jet Toward Region Transverse Region Away Region 0 - η + Transverse Cone: π(0.7) 2 =9π Transverse Region: 2π/3=0.67π φ 2π Cone Leading Jet Cone 2 P T 90 (GeV/c) 0 - η Cone Analysis (Tano, Kovacs, Huston, Bhatti) MAX Data CDF PRELIMINARY MAX Herwig+QFL MAX Pythia6.5+QFL (tuned) MIN Data MIN Herwig+QFL MIN Pythia6.5+QFL (tuned) Sum the P T of charged particles in two cones of radius 0.7 at the same η as the leading jet but with Φ Φ = 90 o. Plot the cone with the maximum and minimum PT sum versus the E T of the leading (calorimeter) jet E T of leading jet (GeV) Rick Field Florida/CDF/CMS Page 3

14 P T 90 (GeV/c) CDF PRELIMINARY MAX Data MAX Herwig+QFL MAX Pythia6.5+QFL (tuned) MIN Data MIN Herwig+QFL MIN Pythia6.5+QFL (tuned) Energy Dependence of the Underlying Event Cone Analysis 6 (Tano, Kovacs, Huston, Bhatti) 630 GeV P T 90 (GeV/c),800 GeV PYTHIA 6.5 P T0 =.4 GeV MAX Data CDF PRELIMINARY MAX Herwig+QFL MAX Pythia6.5+QFL (tuned) MIN Data MIN Herwig+QFL MIN Pythia6.5+QFL (tuned) E T of leading Jet (GeV) PYTHIA 6.5 P T0 = 2.0 GeV Sum the P T of charged particles (p T > GeV/c) in two cones of radius 0.7 at the same η as the leading jet but with Φ Φ = 90 o. Plot the cone with the maximum and minimum PT sum versus the E T of the leading (calorimeter) jet. Note that PYTHIA 6.5 is tuned at 630 GeV with P T0 =.4 GeV and at,800 GeV with P T0 = 2.0 GeV. This implies that ε = PARP(90) should be around 0.30 instead of the 0.6 (default). For the MIN cone 0.25 GeV/c in radius R = 0.7 implies a PT sum density of dpt sum /dηdφ = 0.6 GeV/c and.4 GeV/c in the MAX cone implies dpt sum /dηdφ = 0.9 GeV/c (average PT sum density of 4 GeV/c per unit η-φ) E T of leading jet (GeV) Rick Field Florida/CDF/CMS Page 4

15 Transverse Charged Densities Energy Dependence Charged PTsum Density (GeV) "Transverse" Charged PTsum Density: dptsum/dηdφ 0.60 ε = 0.25 HERWIG ε = ε = 0 CTEQ5L Pythia (Set A) 630 GeV η <.0 PT> GeV PT(charged jet#) (GeV/c) Charged PTsum Density (GeV) "Min Transverse" PTsum Density: dptsum/dηdφ 0.3 Pythia (Set A) HERWIG 6.4 ε = CTEQ5L ε = 0.6 ε = GeV η <.0 PT> GeV PT(charged jet#) (GeV/c) Shows the transverse charged PT sum density ( η <, P T > GeV) versus P T (charged jet#) at 630 GeV predicted by HERWIG 6.4 (P T (hard) > 3 GeV/c, CTEQ5L) and a tuned version of PYTHIA (P T (hard) > 0, CTEQ5L, Set A, ε = 0, ε = 0.6 (default) and ε = 0.25 (preferred)). Also shown are the PT sum densities (0.6 GeV/c and 4 GeV/c) determined from the Tano, Kovacs, Huston, and Bhatti transverse cone analysis at 630 GeV. PT0 (GeV/c) PYTHIA Hard-Scattering Cut-Off PT0 00,000 0,000 00,000 Reference point E 0 =.8 TeV ε = 0.25 (Set A)) ε = 0.6 (default) CM Energy W (GeV) Rick Field Florida/CDF/CMS Page 5

16 Charged PTsum Density (GeV) Transverse Charged Densities "Transverse" Charged PTsum Density: dptsum/dηdφ HERWIG 6.4 ε = 0 Pythia (Set A) ε = PT(charged jet#) (GeV/c) Energy Dependence ε = 0.6 CTEQ5L 630 GeV η <.0 PT> GeV Shows the transverse charged PT sum density ( η <, P T > GeV) versus P T (charged jet#) at 630 GeV predicted by HERWIG 6.4 (P T (hard) > 3 GeV/c, CTEQ5L) and a tuned version of PYTHIA (P T (hard) > 0, CTEQ5L, Set A, ε = 0, ε = 0.6 (default) and ε = 0.25 (preferred)). Also shown are the PT sum densities (0.6 GeV/c and 4 GeV/c) determined from the Tano, Kovacs, Huston, and Bhatti transverse cone analysis at 630 GeV. Charged PTsum Density (GeV) Lowering P T0 at 630 GeV (i.e. increasing ε) increases UE activity resulting in less energy dependence. "Min Transverse" PTsum Density: dptsum/dηdφ Pythia (Set A) ε = 0.25 Increasing ε produces less energy dependence for the ε = 0.6 UE resulting ε = 0 in less UE activity at the LHC! PT0 (GeV/c) PYTHIA PT(charged jet#) (GeV/c) HERWIG 6.4 Hard-Scattering Cut-Off PT0 ε = 0.25 (Set A)) CTEQ5L 630 GeV η <.0 PT> GeV ε = 0.6 (default) CM Energy W (GeV) Rick Field Fermilab MC Workshop Reference point October 4, 2002! E 0 =.8 TeV 00,000 0,000 00,000 Rick Field Florida/CDF/CMS Page 6

17 CDF Run P (Z) T UE Parameters PYTHIA 6.2 CTEQ5L Parameter Tune A Tune A25 MSTP(8) MSTP(82) 4 4 PARP(82) 2.0 GeV 2.0 GeV PARP(83) PARP(84) Tune A GeV PT Distribution /N dn/dpt σ = Z-Boson Transverse Momentum σ = 2.5 CDF Run Data PYTHIA Tune A PYTHIA Tune A25 PYTHIA Tune A50 σ = 5.0 CDF Run published.8 TeV Normalized to PARP(85) PARP(86) Z-Boson PT (GeV/c) ISR Parameter PARP(89) PARP(90) PARP(67) MSTP(9).8 TeV TeV TeV Shows the Run Z-boson p T distribution (<p T (Z)>.5 GeV/c) compared with PYTHIA Tune A (<p T (Z)> = 9.7 GeV/c), Tune A25 (<p T (Z)> = 0. GeV/c), and Tune A50 (<p T (Z)> =.2 GeV/c). PARP(9) PARP(93) Intrensic KT Vary the intrensic KT! Rick Field Florida/CDF/CMS Page 7

18 UE Parameters ISR Parameters Intrensic KT CDF Run P (Z) T PYTHIA 6.2 CTEQ5L Parameter MSTP(8) MSTP(82) PARP(82) PARP(83) PARP(84) PARP(85) PARP(86) PARP(89) PARP(90) PARP(62) PARP(64) PARP(67) MSTP(9) PARP(9) PARP(93) Tune A GeV TeV Tune AW GeV TeV Tune used by the CDF-EWK group! PT Distribution /N dn/dpt Z-Boson Transverse Momentum CDF Run Data PYTHIA Tune A PYTHIA Tune AW Z-Boson PT (GeV/c) CDF Run published.8 TeV Normalized to Shows the Run Z-boson p T distribution (<p T (Z)>.5 GeV/c) compared with PYTHIA Tune A (<p T (Z)> = 9.7 GeV/c), and PYTHIA Tune AW (<p T (Z)> =.7 GeV/c). Effective Q cut-off, below which space-like showers are not evolved. The Q 2 = k T2 in α s for space-like showers is scaled by PARP(64)! Rick Field Florida/CDF/CMS Page 8

19 Jet-Jet Correlations (DØ) Jet#-Jet#2 φ Distribution φ Jet#-Jet#2 MidPoint Cone Algorithm (R = 0.7, f merge = ) L= 50 pb - (Phys. Rev. Lett (2005)) Data/NLO agreement good. Data/HERWIG agreement good. Data/PYTHIA agreement good provided PARP(67) = (i.e. like Tune A, best fit 2.5). Rick Field Florida/CDF/CMS Page 9

20 CDF Run P (Z) T PYTHIA 6.2 CTEQ5L Z-Boson Transverse Momentum UE Parameters Parameter MSTP(8) MSTP(82) PARP(82) PARP(83) PARP(84) PARP(85) Tune DW 4.9 GeV.0 Tune AW GeV 0.9 PT Distribution /N dn/dpt CDF Run Data PYTHIA Tune DW HERWIG CDF Run published.8 TeV Normalized to ISR Parameters PARP(86) PARP(89) PARP(90) PARP(62) PARP(64) PARP(67).0.8 TeV TeV Z-Boson PT (GeV/c) Shows the Run Z-boson p T distribution (<p T (Z)>.5 GeV/c) compared with PYTHIA Tune DW, and HERWIG. MSTP(9) PARP(9) PARP(93) Intrensic KT Tune DW uses D0 s perfered value of PARP(67)! Tune DW has a lower value of PARP(67) and slightly more MPI! Rick Field Florida/CDF/CMS Page 20

21 All use LO α s with Λ = 92 MeV! Parameter Tune AW Tune DW Tune D6 PYTHIA 6.2 Tunes PDF CTEQ5L CTEQ5L CTEQ6L UE Parameters MSTP(8) MSTP(82) PARP(82) GeV 4.9 GeV 4.8 GeV Uses CTEQ6L PARP(83) PARP(84) PARP(85) Tune A energy dependence! ISR Parameter PARP(86) PARP(89) TeV.0.8 TeV.0.8 TeV PARP(90) PARP(62) PARP(64) PARP(67) MSTP(9) PARP(9) PARP(93) Intrinsic KT Rick Field Florida/CDF/CMS Page 2

22 All use LO α s with Λ = 92 MeV! Parameter PYTHIA 6.2 Tunes Tune DWT Tune D6T ATLAS PDF CTEQ5L CTEQ6L CTEQ5L MSTP(8) UE Parameters MSTP(82) PARP(82).9409 GeV.8387 GeV.8 GeV PARP(83) PARP(84) ATLAS energy dependence! PARP(85) ISR Parameter PARP(86) PARP(89).0.96 TeV.0.96 TeV TeV PARP(90) PARP(62) PARP(64) PARP(67) MSTP(9) PARP(9) PARP(93) Intrinsic KT Rick Field Florida/CDF/CMS Page 22

23 PYTHIA 6.2 Tunes All use LO α s with Λ = 92 MeV! Tune A UE Parameters ISR Parameter Tune D Intrinsic KT Parameter Tune DWT Tune D6T ATLAS PDF CTEQ5L CTEQ6L CTEQ5L MSTP(8) MSTP(82) PARP(82).9409 GeV.8387 GeV.8 GeV PARP(83) PARP(84) Tune AW Tune B Tune BW PARP(85) PARP(86).0.0 PARP(89).96 TeV.96 TeV PARP(90) PARP(62) PARP(64) PARP(67) MSTP(9) PARP(9) Tune 2. DW 2. PARP(93) TeV Tune D6 5.0 ATLAS energy dependence! Tune D6T Rick Field Florida/CDF/CMS Page 23

24 "Transverse" Charged Density Min-Bias Associated Charged Particle Density 35% more at RHIC means 26% less at the LHC! RDF Preliminary generator level Min-Bias 0.2 TeV ~.35 PY Tune DW PY Tune DWT Charged Particles ( η <.0, PT> GeV/c) PTmax (GeV/c) "Transverse" Charged Density.6.2 RDF Preliminary generator level Min-Bias 4 TeV PY Tune DWT ~.35 Charged Particles ( η <.0, PT> GeV/c) PTmax (GeV/c) PY Tune DW RHIC PTmax Direction φ Toward Transverse Transverse 0.2 TeV 4 TeV (~factor of 70 increase) LHC PTmax Direction φ Toward Transverse Transverse Away Away Shows the associated charged particle density in the transverse regions as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at 0.2 TeV and 4 TeV from PYTHIA Tune DW and Tune DWT at the particle level (i.e. generator level). The STAR data from RHIC favors Tune DW! Rick Field Florida/CDF/CMS Page 24

25 Min-Bias Associated Charged Particle Density "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level ~.9 ~2.7 Min-Bias Charged Particles ( η <.0, PT> GeV/c) PTmax (GeV/c) 0.2 TeV 4 TeV.96 TeV RHIC PTmax Direction φ Toward Transverse Transverse 0.2 TeV.96 TeV (UE increase ~2.7 times) Tevatron PTmax Direction φ Toward Transverse Transverse.96 TeV 4 TeV (UE increase ~.9 times) LHC PTmax Direction φ Toward Transverse Transverse Away Away Away Shows the associated charged particle density in the transverse region as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at 0.2 TeV,.96 TeV and 4 TeV predicted by PYTHIA Tune DW at the particle level (i.e. generator level). Rick Field Florida/CDF/CMS Page 25

26 The Underlying Event at STAR At STAR they have measured the underlying event at W = 200 GeV ( η <, p T > 0.2 GeV) and compared their uncorrected data with PYTHIA Tune A + STAR-SIM. Rick Field Florida/CDF/CMS Page 26

27 The Underlying Event at STAR At STAR they have measured the underlying event at W = 200 GeV ( η <, p T > 0.2 GeV) and compared their uncorrected data with PYTHIA Tune A + STAR-SIM. Rick Field Florida/CDF/CMS Page 27

28 Transverse Charged Particle Density "Transverse" Charged Density RDF LHC Prediction! RDF Preliminary generator level Min-Bias.96 TeV PY64 Tune S320 PY64 Tune P329 PY64 Tune N PTmax (GeV/c) PY Tune A Charged Particles ( η <.0, PT> GeV/c) "Transverse" Charged Density.6.2 RDF Preliminary generator level PY ATLAS PY Tune A PY64 Tune S320 PY Tune DW Min-Bias 4 TeV Charged Particles ( η <.0, PT> GeV/c) PTmax (GeV/c) PY64 Tune P329 PY Tune DWT PTmax Direction PTmax Direction φ φ Toward Toward Transverse Transverse Tevatron LHC Transverse Transverse Away Away Shows the associated charged particle density in the transverse region as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at.96 TeV from PYTHIA Tune A, Tune S320, Tune N324, and Tune P329 at the particle level (i.e. generator level). Extrapolations of PYTHIA Tune A, Tune DW, Tune DWT, Tune S320, Tune P329, and pyatlas to the LHC. Rick Field Florida/CDF/CMS Page 28

29 Transverse Charged Particle Density "Transverse" Charged Density RDF LHC Prediction! RDF Preliminary generator level "Transverse" Charged Density PY Tune A PY64 Tune P329 PY64 Tune N324 PY Tune A PY64 Tune S320 PY64 Tune S320 PY Tune DW Min-Bias Min-Bias Charged Particles If the ( η <.0, LHC PT> GeV/c) data are 4 not TeV in.96 TeV Charged Particles ( η <.0, PT> GeV/c) the 4range 6 8 shown 20 0here then PTmax (GeV/c) PTmax (GeV/c) PTmax Direction Transverse Toward Away PY64 Tune P329 φ Transverse Tevatron.6.2 RDF Preliminary generator level we learn new (QCD) physics! Rick Field October 3, 2009 LHC PTmax Direction Transverse Toward Away PY ATLAS φ Transverse PY Tune DWT Shows the associated charged particle density in the transverse region as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at.96 TeV from PYTHIA Tune A, Tune S320, Tune N324, and Tune P329 at the particle level (i.e. generator level). Extrapolations of PYTHIA Tune A, Tune DW, Tune DWT, Tune S320, Tune P329, and pyatlas to the LHC. Rick Field Florida/CDF/CMS Page 29

30 Transverse Charged Density PTmax Direction φ Toward Transverse Transverse Away ChgJet# Direction φ Toward Transverse Transverse Away Muon-Pair Direction φ Toward "Transverse" Charged Density.6.2 RDF Preliminary py Tune DW generator level PTmax DY(muon-pair) 70 < M(pair) < 0 GeV ChgJet# PT(chgjet#) or PTmax or PT(pair) (GeV/c) Charged Particles ( η <.0, PT> GeV/c) Transverse Transverse Away Shows the charged particle density in the transverse region for charged particles (p T > GeV/c, η < ) at as defined by PTmax, PT(chgjet#), and PT(muon-pair) from PYTHIA Tune DW at the particle level (i.e. generator level). Charged particle jets are constructed using the Anti-KT algorithm with d =. Rick Field Florida/CDF/CMS Page 30

31 Min-Bias Associated Charged Particle Density "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level Min-Bias PTmax (GeV/c) 4 TeV.96 TeV 0.9 TeV 0.2 TeV 0 TeV Charged Particles ( η <.0, PT> GeV/c) "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level Tevatron RHIC LHC Center-of-Mass Energy (TeV) LHC0 PTmax = 5.25 GeV/c LHC4 Charged Particles ( η <.0, PT> GeV/c) RHIC PTmax Direction φ Toward Transverse Transverse 0.2 TeV.96 TeV (UE increase ~2.7 times) Tevatron PTmax Direction φ Toward Transverse Transverse.96 TeV 4 TeV (UE increase ~.9 times) LHC PTmax Direction φ Toward Transverse Transverse Away Away Away Shows the associated charged particle density in the transverse region as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at 0.2 TeV, 0.9 TeV,.96 TeV,, 0 TeV, 4 TeV predicted by PYTHIA Tune DW at the particle Linear scale! level (i.e. generator level). Rick Field Florida/CDF/CMS Page 3

32 Min-Bias Associated Charged Particle Density "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level Min-Bias Charged Particles ( η <.0, PT> GeV/c) PTmax (GeV/c) 4 TeV.96 TeV 0.9 TeV 0.2 TeV 0 TeV "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level RHIC Tevatron Charged Particles ( η <.0, PT> GeV/c) Center-of-Mass Energy (TeV) LHC4 LHC0 LHC7 PTmax = 5.25 GeV/c LHC7 PTmax Direction φ Toward Transverse Transverse Away 4 TeV (UE increase ~20%) Linear on a log plot! LHC4 PTmax Direction φ Toward Transverse Transverse Away Shows the associated charged particle density in the transverse region as a function of PTmax for charged particles (p T > GeV/c, η <, not including PTmax) for min-bias events at 0.2 TeV, 0.9 TeV,.96 TeV,, 0 TeV, 4 TeV predicted by PYTHIA Tune DW at the particle Log scale! level (i.e. generator level). Rick Field Florida/CDF/CMS Page 32

33 Conclusions November 2009 We are making good progress in understanding and modeling the underlying event. RHIC data at 200 GeV are very important! The new Pythia p T ordered tunes (py64 S320 and py64 P329) are very similar to Tune A, Tune AW, and Tune DW. At present the new tunes do not fit the data better than Tune AW and Tune DW. However, the new tune are theoretically preferred! It is clear now that the default value PARP(90) = 0.6 is not correct and the value should be closer to the Tune A value of The new and old PYTHIA tunes are beginning to converge and I believe we are finally in a position to make some legitimate predictions at the LHC! All tunes with the default value PARP(90) = 0.6 are wrong and are overestimating the activity of min-bias and the underlying event at the LHC! This includes all my T tunes and the (old) ATLAS tunes! Need to measure Min-Bias and the underlying event at the LHC as soon as possible to see if there is new QCD physics to be learned! PT0 (GeV/c) Proton Underlying Event Outgoing Parton PYTHIA Final-State Radiation UE&MB@CMS Outgoing Parton PT(hard) Hard-Scattering Cut-Off PT0 ε = 0.25 (Set A)) ε = 0.6 (default) Initial-State Radiation AntiProton Underlying Event 00,000 0,000 00,000 CM Energy W (GeV) Rick Field Florida/CDF/CMS Page 33

34 Transverse Charged Particle Density "Transverse" Charged Density RDF Preliminary Fake Data pydw generator level PTmax Prediction! ChgJet# PTmax or PT(chgjet#) (GeV/c) Charged Particles ( η <2.0, PT> GeV/c) Fake data (from MC) at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) and the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The fake data (from PYTHIA Tune DW) are generated at the particle level (i.e. generator level) assuming M min-bias events at (36,595 events in the plot). PT(chgjet#) Direction Transverse Toward Away φ Transverse PTmax Direction Transverse Toward Away φ Transverse Rick Field MB&UE@CMS Workshop CERN, November 6, 2009 Leading Charged Particle Jet, chgjet#. Leading Charged Particle, PTmax. Rick Field Florida/CDF/CMS Page 34

35 Transverse Charge Density "Transverse" Charged Density.2 RDF Preliminary py Tune DW generator level Prediction! factor of 2! PTmax (GeV/c) Charged Particles ( η <2.0, PT> GeV/c) Rick Field MB&UE@CMS Workshop CERN, November 6, 2009 LHC PTmax Direction φ Toward Transverse Transverse Away (UE increase ~ factor of 2) ~ ~ LHC PTmax Direction φ Toward Transverse Transverse Away Shows the charged particle density in the transverse region for charged particles (p T > GeV/c, η < 2) at and as defined by PTmax from PYTHIA Tune DW and at the particle level (i.e. generator level). Rick Field Florida/CDF/CMS Page 35

36 Transverse Charged Particle Density "Transverse" Charged Density RDF Preliminary Fake Data pydw generator level PTmax Monte-Carlo! ChgJet# Charged Particles ( η <2.0, PT> GeV/c) "Transverse" Charged Density CMS Preliminary data uncorrected pydw + SIM PTmax Real Data! ChgJet# Charged Particles ( η <2.0, PT> GeV/c) PTmax or PT(chgjet#) (GeV/c) PTmax or PT(chgjet#) (GeV/c) Fake data (from MC) at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) and the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The fake data (from PYTHIA Tune DW) are generated at the particle level (i.e. generator level) assuming M min-bias events at (36,595 events in the plot). CMS preliminary data at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) and the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation (26,25 events in the plot). Rick Field Florida/CDF/CMS Page 36

37 Transverse Charged PTsum Density PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ RDF Preliminary Fake Data pydw generator level PTmax Monte-Carlo! ChgJet# PTmax or PT(chgjet#) (GeV/c) Charged Particles ( η <2.0, PT> GeV/c) PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ CMS Preliminary data uncorrected pydw + SIM PTmax Real Data! ChgJet# PTmax or PT(chgjet#) (GeV/c) Charged Particles ( η <2.0, PT> GeV/c) Fake data (from MC) at on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) and the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The fake data (from PYTHIA Tune DW) are generated at the particle level (i.e. generator level) assuming M min-bias events at (36,595 events in the plot). CMS preliminary data at on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) and the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation (26,25 events in the plot). Rick Field Florida/CDF/CMS Page 37

38 PYTHIA Tune DW Charged Particle Density.2 CMS Preliminary data uncorrected pydw + SIM PT(chgjet#) GeV/c CMS preliminary data at and on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation. PT(chgjet#) Direction Charged Particles ( η <2.0, PT> GeV/c) φ CMS "Transverse" Charged Density.2 RDF Preliminary ATLAS corrected data Tune DW generator level PTmax (GeV/c) PTmax Direction φ ATLAS Charged Particles ( η <2.5, PT> GeV/c) ATLAS preliminary data at and on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η < 2.5. The data are corrected and compared with PYTHIA Tune DW at the generator level. Toward Toward Transverse Transverse Transverse Transverse Away Away Rick Field Florida/CDF/CMS Page 38

39 PYTHIA Tune DW Charged Particle Density.2 CMS Preliminary data uncorrected pydw + SIM Ratio PT(chgjet#) GeV/c Ratio: / CMS Preliminary data uncorrected pydw + SIM simulation. / Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) (GeV/c) PT(chgjet#) Direction φ CMS CMS preliminary data at and Ratio of CMS preliminary data at on the transverse charged particle density, and on the transverse charged dn/dηdφ, as defined by the leading charged particle density, dn/dηdφ, as defined by the particle jet (chgjet#) for charged particles with leading charged particle jet (chgjet#) for p T > GeV/c and η < 2. The data are charged particles with p T > GeV/c and η uncorrected and compared with PYTHIA Tune < 2. The data are uncorrected and compared DW after detector simulation. with PYTHIA Tune DW after detector PT(chgjet#) Direction Charged Particles ( η <2.0, PT> GeV/c) φ CMS Toward Toward Transverse Transverse Transverse Transverse Away Away Rick Field Florida/CDF/CMS Page 39

40 PYTHIA Tune DW Ratio: / CMS Preliminary data uncorrected pydw + SIM / Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) (GeV/c) CMS Ratio: / RDF Preliminary ATLAS corrected data pydw generator level / Charged Particles ( η <2.5, PT> GeV/c) PTmax (GeV/c) ATLAS Ratio of CMS preliminary data at and on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector PT(chgjet#) Direction simulation. Toward φ Ratio of the ATLAS preliminary data at and on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η < 2.5. The data are corrected and compared with PYTHIA Tune DW at PTmax Direction the generator level. Toward φ Transverse Transverse Transverse Transverse Away Away Rick Field Florida/CDF/CMS Page 40

41 PYTHIA Tune DW How well did we do at predicting the underlying event at and? "Transverse" Charged Density CMS Preliminary data uncorrected pydw + SIM PTmax Tune DW ChgJet# Charged Particles ( η <2.0, PT> GeV/c) PTmax or PT(chgjet#) (GeV/c) Charged Particle Density.2 CMS Preliminary data uncorrected pydw + SIM Tune DW Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c I am surprised that the Tunes did not do a better job of predicting the behavior of the underlying event at and! Ratio: / CMS Preliminary data uncorrected pydw + SIM / Tune DW Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) (GeV/c) Rick Field Florida/CDF/CMS Page 4

42 PYTHIA Tune DW How well did we do at predicting the underlying event at and? "Transverse" Charged Density CMS Preliminary data uncorrected pydw + SIM PTmax Tune DW ChgJet# Charged Particles ( η <2.0, PT> GeV/c) PTmax or PT(chgjet#) (GeV/c) Charged Particle Density.2 CMS Preliminary data uncorrected pydw + SIM Tune DW Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c I am surprised that the Tunes did as well as they did at predicting the behavior of the underlying event at and! Ratio: / CMS Preliminary data uncorrected pydw + SIM / Tune DW Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) (GeV/c) Rick Field Florida/CDF/CMS Page 42

43 PYTHIA Tune DW How well did we do at predicting the underlying event at and? "Transverse" Charged Density 0.6 CMS Preliminary data uncorrected pydw + SIM PTmax ChgJet# 0.2 Tune DW at charged particles with p Charged Particles ( η <2.0, PT> GeV/c) T > GeV/c. Tune DW Charged Particles ( η <2.0, PT> GeV/c) We do not know if the models correctly PTmax or PT(chgjet#) (GeV/c) describe the UE at lower p T values! PT(chgjet#) GeV/c Charged Particle Density.2 CMS Preliminary data uncorrected pydw + SIM Warning! All the UE studies look I am surprised that the Tunes did as well as they did at predicting the behavior of the underlying event at and! Ratio: / CMS Preliminary data uncorrected pydw + SIM / Tune DW Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) (GeV/c) Rick Field Florida/CDF/CMS Page 43

44 ATLAS Tune AMBT Judith Katzy LPCC MB&UE working group meeting, May 3, 200. Emily Nurse ICHEP, July 24, 200. ATLAS-CONF Rick Field Florida/CDF/CMS Page 44

45 ATLAS Tune AMBT Subset of the min-bias data! Attempt to fit a subset of the min-bias data (Nchg 6) where the contamination due to diffraction is expected to be small! Rick Field Florida/CDF/CMS Page 45

46 PYTHIA Tune Z All my previous tunes (A, DW, DWT, D6, D6T, CW, X, and X2) were PYTHIA 6.4 tunes using the old Q 2 -ordered parton showers and the old MPI model (really 6.2 tunes)! I believe that it is time to move to PYTHIA 6.4 (p T -ordered parton showers and new MPI model)! Tune Z: I started with the parameters of ATLAS Tune AMBT, but I changed LO* to CTEQ5L and I varied PARP(82) and PARP(90) to get a very good fit of the CMS UE data at 900 GeV and. The ATLAS Tune AMBT was designed to fit the inelastic data for Nchg 6 and to fit the PTmax UE data with PTmax > 0 GeV/c. Tune AMBT is primarily a min-bias tune, while Tune Z is a UE tune! Proton PARP(90) Color Connections Underlying Event Outgoing Parton Final-State Radiation PARP(82) Diffraction Outgoing Parton PT(hard) UE&MB@CMS Initial-State Radiation Proton Underlying Event Rick Field Florida/CDF/CMS Page 46

47 PYTHIA Tune Z Parameter Tune Z (R. Field CMS) Tune AMBT (ATLAS) Parton Distribution Function CTEQ5L LO* Parameters not shown are the PYTHIA 6.4 defaults! PARP(82) MPI Cut-off PARP(89) Reference energy, E PARP(90) MPI Energy Extrapolation PARP(77) CR Suppression PARP(78) CR Strength PARP(80) Probability colored parton from BBR PARP(83) Matter fraction in core PARP(84) Core of matter overlap PARP(62) ISR Cut-off PARP(93) primordial kt-max MSTP(8) MPI, ISR, FSR, BBR model 2 2 MSTP(82) Double gaussion matter distribution 4 4 MSTP(9) Gaussian primordial kt MSTP(95) strategy for color reconnection 6 6 Rick Field Florida/CDF/CMS Page 47

48 CMS UE Data Charged Particle Density.2 CMS Preliminary data uncorrected Theory + SIM D6T PT(chgjet#) GeV/c CMS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are uncorrected and compared with PYTHIA Tune DW and D6T after detector simulation (SIM). Color reconnection suppression. Color reconnection strength. DW CMS Tune Z (CTEQ5L) PARP(82) =.932 PARP(90) = PARP(77) =.06 PARP(78) = 38 Charged Particle Density.2 CMS Preliminary data uncorrected pyz + SIM Tune Z Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c CMS CMS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are uncorrected and compared with PYTHIA Tune Z after detector simulation (SIM). Tune Z is a PYTHIA 6.4 using p T -ordered parton showers and the new MPI model! Rick Field Florida/CDF/CMS Page 48

49 PYTHIA 6.2 Tunes Parameter Tune AW Tune DW Tune D6 PDF CTEQ5L CTEQ5L CTEQ6L UE Parameters MSTP(8) MSTP(82) PARP(82) GeV 4.9 GeV 4.8 GeV Uses CTEQ6L PARP(83) PARP(84) PARP(85) ISR Parameter PARP(86) PARP(89) PARP(90) PARP(62) TeV TeV TeV Reduce PARP(82) by factor of.8/.9 = 0.95 Everything else the same! PARP(64) PARP(67) MSTP(9) PARP(9) Tune A energy dependence! (not the default) PARP(93) Intrinsic KT CMS: We wanted a CTEQ6L version of Tune Z in a hurry! Rick Field Florida/CDF/CMS Page 49

50 PYTHIA Tune Z2 My guess! Parameter Tune Z (R. Field CMS) Tune Z2 (R. Field CMS) Parton Distribution Function CTEQ5L CTEQ6L PARP(82) MPI Cut-off PARP(89) Reference energy, E PARP(90) MPI Energy Extrapolation PARP(77) CR Suppression PARP(78) CR Strength PARP(80) Probability colored parton from BBR Reduce PARP(82) by factor of.83/.93 = 0.95 Everything else the same! PARP(83) Matter fraction in core PARP(84) Core of matter overlap PARP(62) ISR Cut-off PARP(93) primordial kt-max MSTP(8) MPI, ISR, FSR, BBR model 2 2 MSTP(82) Double gaussion matter distribution 4 4 MSTP(9) Gaussian primordial kt MSTP(95) strategy for color reconnection 6 6 Rick Field Florida/CDF/CMS Page 50

51 PYTHIA Tune Z2 My guess! Parameter Tune Z (R. Field CMS) Tune Z2 (R. Field CMS) Parton Distribution Function CTEQ5L CTEQ6L PARP(82) MPI Cut-off PARP(89) Reference energy, E PARP(90) MPI Energy Extrapolation PARP(77) CR Suppression PARP(78) CR Strength PARP(80) Probability colored parton from BBR Reduce PARP(82) by factor of.83/.93 = 0.95 Everything else the same! PARP(83) Matter fraction in core PARP(84) Core of matter overlap PARP(62) ISR Cut-off PARP(93) primordial kt-max PARP(90) same For Z and Z2! MSTP(8) MPI, ISR, FSR, BBR model 2 2 MSTP(82) Double gaussion matter distribution 4 4 MSTP(9) Gaussian primordial kt MSTP(95) strategy for color reconnection 6 6 Rick Field Florida/CDF/CMS Page 5

52 PYTHIA 8 Tunes R. Corke and T. Sjöstrand CTEQ6L MRST LO** CTEQ6L PT0 = PARP(82) ε = PARP(90) Tevatron LHC p T0 (W)=p T0 (W/W 0 ) ε ε = PARP(90) p T0 = PARP(82) W = E cm Rick Field Florida/CDF/CMS Page 52

53 PYTHIA Tune Z2 Parameter Parton Distribution Function PARP(82) MPI Cut-off PARP(89) Reference energy, E0 PARP(90) MPI Energy Extrapolation PARP(77) CR Suppression PARP(78) CR Strength PARP(80) Probability colored parton from BBR PARP(83) Matter fraction in core PARP(84) Core of matter overlap PARP(62) ISR Cut-off PARP(93) primordial kt-max MSTP(8) MPI, ISR, FSR, BBR model MSTP(82) Double gaussion matter distribution MSTP(9) Gaussian primordial kt MSTP(95) strategy for color reconnection Tune Z2 (R. Field CMS) CTEQ6L PY8 Tune C4 (Corke-Sjöstrand) CTEQ6L PARP(90) much different! Rick Field Florida/CDF/CMS Page 53

54 CMS UE Data Charged Particle Density.6.2 CMS Preliminary data corrected Tune Z generator level PT(chgjet#) GeV/c CMS Tune Z Charged Particles ( η <2.0, PT> GeV/c) CMS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA Tune Z at the generator level. PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ CMS Preliminary data corrected Tune Z generator level CMS Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c Tune Z CMS preliminary data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA Tune Z at the generator level. CMS corrected data! Very nice agreement! CMS corrected data! Rick Field Florida/CDF/CMS Page 54

55 PYTHIA 6.4 Tune Z2 Charged Particle Density.6.2 CMS Preliminary data corrected Tune Z2 generator level Tune Z2 Charged Particles ( η <2.0, PT> GeV/c) PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ CMS Preliminary data corrected Tune Z2 generator level Tune Z2 Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c PT(chgjet#) GeV/c CMS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA Tune Z2 at the generator level. CMS preliminary data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA Tune Z2 at the generator level. CMS corrected data! Not good! Bad energy dependence! CMS corrected data! Rick Field Florida/CDF/CMS Page 55

56 PYTHIA 8 Tune C4 Charged Particle Density.6.2 CMS Preliminary data corrected PY8 Tune C4 generator level PY8 Tune C4 Charged Particles ( η <2.0, PT> GeV/c) PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ CMS Preliminary data corrected PY8 Tune C4 generator level PY8 Tune C4 Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c PT(chgjet#) GeV/c CMS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA 8 Tune C4 at the generator level. CMS preliminary data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0. The data are corrected and compared with PYTHIA 8 Tune C4 at the generator level. CMS corrected data! Not good! PTsum too small! CMS corrected data! Rick Field Florida/CDF/CMS Page 56

57 Transverse Ratio: PTsum/Nchg PTsum/Nchg (GeV/c) "Transverse" Charged Particle Ratio: PTsum/Nchg CMS Preliminary data corrected Tune Z generator level Tune Z PTsum/Nchg (GeV/c) "Transverse" Charged Particle Ratio: PTsum/Nchg CMS Preliminary data corrected Tune Z2 generator level Tune Z2 Charged Particles ( η <2.0, PT> GeV/c) Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c PT(chgjet#) GeV/c CMS preliminary data at and 7 TeV on the transverse ratio PTsum/Nchg as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 compared with PYTHIA Tune Z, Z2, and PY8C4 at the generator level. Z good! PY8C4 and Z2 Bad! PTsum/Nchg (GeV/c) "Transverse" Charged Particle Ratio: PTsum/Nchg CMS Preliminary data corrected PY8 Tune C4 generator level PY8 Tune C4 Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c Rick Field Florida/CDF/CMS Page 57

58 Energy Dependence Charged Density Ratio "Transverse" Charged Particle Density: Ratio CMS Preliminary data corrected generator level theory Z2 Z PY8C4 Charged Density Ratio "Transverse" Charged PTsum Density: Ratio CMS Preliminary data corrected generator level theory Z2 Z PY8C4 divided by Charged Particles ( η <2.0, PT> GeV/c) divided by Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c PT(chgjet#) GeV/c CMS data on the energy dependence ( divided by ) of the transverse charged particle density as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 compared with PYTHIA Tune Z, Z2, and PY8C4 at the generator level. CMS data on the energy dependence ( divided by ) of the transverse charged PTsum density as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 compared with PYTHIA Tune Z, Z2, and PY8C4 at the generator level. CMS corrected data! Z and PY8C4 good! Z2 Bad! CMS corrected data! Rick Field Florida/CDF/CMS Page 58

59 Charged Density Ratio Energy Dependence "Transverse" Charged Particle Density: Ratio CMS Preliminary data corrected generator level theory Z2 divided by CTEQ6L: PARP(90) =0.275 Charged Particles ( η <2.0, PT> GeV/c) PT(chgjet#) GeV/c CMS data on the energy dependence ( divided by ) of the transverse charged particle density as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 compared with PYTHIA Tune Z, Z2, and PY8C4 at the generator level. Z PY8C4 CTEQ6L: PARP(90) = 0.9 "Transverse" Charged PTsum Density: Ratio Charged Density Ratio CMS Preliminary data corrected generator level theory divided by Charged Particles ( η <2.0, PT> GeV/c) CTEQ5L: PARP(90) =0.275 Z2 PT(chgjet#) GeV/c CMS data on the energy dependence ( divided by ) of the transverse charged PTsum density as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 compared with PYTHIA Tune Z, Z2, and PY8C4 at the generator level. Z PY8C4 CMS corrected data! Duh! The energy dependence depends on Z and PY8C4 good! Z2 Bad! both PARP(90) and the structure function! CMS corrected data! Rick Field Florida/CDF/CMS Page 59

60 ATLAS UE Data "Transverse" Charged Density.2 RDF Preliminary ATLAS corrected data Tune Z generator level ATLAS Tune Z Charged Particles ( η <2.5, PT> GeV/c) PTsum Density (GeV/c).5.0 "Transverse" Charged PTsum Density: dpt/dηdφ RDF Preliminary ATLAS corrected data Tune Z generator level ATLAS Tune Z Charged Particles ( η <2.5, PT> GeV/c) PTmax (GeV/c) PTmax (GeV/c) ATLAS published data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η < 2.5. The data are corrected and compared with PYTHIA Tune Z at the generator level. ATLAS published data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η < 2.5. The data are corrected and compared with PYTHIA Tune Z at the generrator level. ATLAS publication arxiv: December 3, 200 Rick Field Florida/CDF/CMS Page 60

61 CMS-ATLAS UE Data Charged Particle Density.6.2 RDF Preliminary data corrected Tune Z generator level ATLAS: PTmax CMS: Chgjet# Charged Particles (PT > GeV/c) PTmax or PT(chgjet#) (GeV/c) CMS (red) ATLAS (blue) Tune Z CMS preliminary data at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle jet (chgjet#) for charged particles with p T > GeV/c and η < 2.0 together with the ATLAS published data at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η < 2.5 The data are corrected and compared with PYTHIA Tune Z at the generator level. Charged Particle Density.6.2 RDF Preliminary data corrected Tune Z generator level Charged Particles (PT > GeV/c) PTmax or PT(chgjet#) (GeV/c) CMS (red) ATLAS (blue) Tune Z Amazing agreement! Rick Field Florida/CDF/CMS Page 6

62 ATLAS UE Data "Transverse" Charged Density RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z PT > GeV/c PTmax (GeV/c) PT > 0. GeV/c ATLAS Charged Particles ( η <2.5) PTsum Density (GeV/c) "Transverse" Charged PTsum Density: dpt/dηdφ RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z PT > GeV/c PTmax (GeV/c) PT > 0. GeV/c ATLAS Charged Particles ( η <2.5) ATLAS published data at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and p T > 0. GeV/c ( η < 2.5). The data are corrected and compared with PYTHIA Tune Z at the generator level. ATLAS published data at on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and p T > 0. GeV/c ( η < 2.5). The data are corrected and compared with PYTHIA Tune Z at the generator level. ATLAS publication arxiv: December 3, 200 Rick Field Florida/CDF/CMS Page 62

63 ATLAS UE Data "Transverse" Charged Density RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z "Transverse" Ratio 0./ PT > GeV/c.0 PT > 0. GeV/c Charged Particles ( η <2.5) Charge PTsum Density PTmax (GeV/c) ATLAS published data at on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and p T > 0. GeV/c ( η < 2.5). The data are corrected and compared with PYTHIA Tune Z at the generator level. "Transverse" Ratio: PT > 0. and > GeV/c ATLAS PTsum Density (GeV/c).0 "Transverse" Charged PTsum Density: dpt/dηdφ 2.5 RDF Preliminary ATLAS corrected data 2.0 Tune Z generator level RDF Preliminary ATLAS corrected data Charge Particle Density Tune Z.5 Tune Z generator level PT > GeV/c PTmax (GeV/c) Charged Particles ( η <2.5) PT > 0. GeV/c Charged Particles ( η <2.5) ATLAS published data at on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and p T > 0. GeV/c ( η < 2.5). The data are corrected and compared with PYTHIA Tune Z at the generator level PTmax (GeV/c) ATLAS publication arxiv: December 3, 200 ATLAS Rick Field Florida/CDF/CMS Page 63

64 ATLAS UE Data "Transverse" Charged Density.2 RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z PTmax (GeV/c) ATLAS Charged Particles ( η <, PT> GeV/c) ATLAS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η <. The data are corrected and compared with PYTHIA Tune Z at the generator level. PTsum Density (GeV/c).5.0 "Transverse" Charged PTsum Density: dpt/dηdφ RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z Charged Particles ( η <, PT > GeV/c) PTmax (GeV/c) ATLAS ATLAS preliminary data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η <. The data are corrected and compared with PYTHIA Tune Z at the generrator level. ATLAS-CONF February 2, 20 Rick Field Florida/CDF/CMS Page 64

65 ATLAS UE Data "Transverse" Charged Density.2 RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z PTmax (GeV/c) ATLAS Charged Particles ( η <, PT> GeV/c) ATLAS preliminary data at and 7 TeV on the transverse charged particle density, dn/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η <. The data are corrected and compared with PYTHIA Tune Z at the generator level. PTsum Density (GeV/c).5.0 "Transverse" Charged PTsum Density: dpt/dηdφ RDF Preliminary ATLAS corrected data Tune Z generator level Tune Z Charged Particles ( η <, PT > GeV/c) PTmax (GeV/c) ATLAS ATLAS preliminary data at and 7 TeV on the transverse charged PTsum density, dpt/dηdφ, as defined by the leading charged particle (PTmax) for charged particles with p T > GeV/c and η <. The data are corrected and compared with PYTHIA Tune Z at the generrator level. ATLAS-CONF February 2, 20 Rick Field Florida/CDF/CMS Page 65