HEP Seminar Tevatron Energy Scan Findings Surprises Rick

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HEP Seminar Tevatron Energy Scan: Findings & Surprises Rick Field University of Florida Outline

HEP Seminar Tevatron Energy Scan: Findings & Surprises Rick Field University of Florida Outline of Talk Æ CDF data from the Tevatron Energy Scan. Æ The overall event topology for events with at least 1 charged particle. Æ The “trans. MAX”, “trans. MIN”, “trans. AVE” and “trans. DIF” UE observables. Æ Mapping out the energy dependence: Tevatron to the LHC! Æ Comparisions with PYTHIA 6. 4 Tune Z 1 & Z 2* and PYTHIA 8 Tune 4 C*. Æ Summary & Conclusions. HEP Seminar - Baylor Waco, January 21, 2014 CDF Run 2 300 Ge. V, 900 Ge. V, 1. 96 Te. V Rick Field – Florida/CDF/CMS at the LHC 900 Ge. V, 7 & 8 Te. V 1

QCD Monte-Carlo Models: High Transverse Momentum Jets “Hard Scattering” Component “Underlying Event” Æ Start

QCD Monte-Carlo Models: High Transverse Momentum Jets “Hard Scattering” Component “Underlying Event” Æ 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). Æ 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“jet” an unavoidable Æ Of course the outgoing colored partons fragment into hadron and inevitably “underlying event” background to most collider observables and observables receive contributions from initial and final-state radiation. having good understand of it leads to more precise collider measurements! HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 2

Proton-Proton Collisions stot = s. EL + s. SD IN + s. DD +

Proton-Proton Collisions stot = s. EL + s. SD IN + s. DD + s. HC ND “Inelastic Non-Diffractive Component” The “hard core” component contains both “hard” and “soft” collisions. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 3

The Inelastic Non-Diffractive Cross-Section Occasionally one of the parton-parton collisions is hard (p. T

The Inelastic Non-Diffractive Cross-Section Occasionally one of the parton-parton collisions is hard (p. T > ≈2 Ge. V/c) Majority of “minbias” events! “Semi-hard” parton collision (p. T < ≈2 Ge. V/c) + +… HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS Multiple-parton interactions (MPI)! 4

The “Underlying Event” Select inelastic non-diffractive events that contain a hard scattering Hard parton-parton

The “Underlying Event” Select inelastic non-diffractive events that contain a hard scattering Hard parton-parton collisions is hard (p. T > ≈2 Ge. V/c) 1/(p. T)4→ 1/(p. T 2+p. T 02)2 The “underlying-event” (UE)! “Semi-hard” parton collision (p. T < ≈2 Ge. V/c) + Given that you have one hard scattering it is more probable to have MPI! Hence, the UE has more activity than “min-bias”. HEP Seminar - Baylor Waco, January 21, 2014 + Rick Field – Florida/CDF/CMS +… Multiple-parton interactions (MPI)! 5

Allow leading hard scattering to go to zero p. T with same cut -off

Allow leading hard scattering to go to zero p. T with same cut -off as the MPI! Model of s. ND 1/(p. T)4→ 1/(p. T 2+p. T 02)2 Model of the inelastic nondiffractive cross section! “Semi-hard” parton collision (p. T < ≈2 Ge. V/c) + +… HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS Multiple-parton interactions (MPI)! 6

UE Tunes Allow primary hard-scattering to go to p. T = 0 with same

UE Tunes Allow primary hard-scattering to go to p. T = 0 with same cut-off! “Underlying Event” Fit the “underlying event” in a hard scattering process. All of Rick’s tunes (except X 2): 1/(p. T)4→ 1/(p. T 2+p. T 02)2 A, AWT, DWT, D 6 T, CW, X 1, “Min-Bias” (add (ND)single & double diffraction) and Tune Z 1, are UE tunes! + Predict MB (ND)! Predict MB (IN)! HEP Seminar - Baylor Waco, January 21, 2014 + + +… Rick Field – Florida/CDF/CMS 7

MB Tunes “Underlying Event” Predict the “underlying event” in a hard scattering process! Most

MB Tunes “Underlying Event” Predict the “underlying event” in a hard scattering process! Most of Peter Skand’s tunes: S 320 Perugia 0, S 325 Perugia X, “Min-Bias” (ND) S 326 Perugia 6 are MB tunes! + Fit MB (ND). + + +… HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 8

Tuning PYTHIA 6. 2: Multiple Parton Interaction Parameters Parameter Default PARP(83) 0. 5 Description

Tuning PYTHIA 6. 2: Multiple Parton Interaction Parameters Parameter Default PARP(83) 0. 5 Description Double-Gaussian: Fraction of total hadronic matter within PARP(84) 0. 2 PARP(85) 0. 33 PARP(86) 0. 66 PARP(89) 1 Te. V PARP(82) 1. 9 Ge. V/c PARP(90) 0. 16 Determines the energy dependence of the cut-off PT 0 as follows PT 0(Ecm) = PT 0(Ecm/E 0)e with e = PARP(90) PARP(67) 1. 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. HEP Seminar - Baylor Waco, January 21, 2014 Double-Gaussian: Fraction of the overall hadron radius containing the fraction PARP(83) of the total hadronic matter. Determines the energy Probability that of thethe MPI produces two gluons dependence MPI! with color connections to the “nearest neighbors. ore Hard C Remember the energy dependence of the “underlying event” activity depends on both the Determines the reference energy E. e = PARP(90) and the PDF! Probability that. Affects the MPI theproduces amount two of gluons either as described by PARP(85) or as a closed initial-state radiation! gluon loop. The remaining fraction consists of quark-antiquark pairs. Determine by comparing with 630 Ge. V data! 0 The cut-off PT 0 that regulates the 2 -to-2 scattering divergence 1/PT 4→ 1/(PT 2+PT 02)2 Rick Field – Florida/CDF/CMS Take E 0 = 1. 8 Te. V Reference point at 1. 8 Te. V 9

Traditional Approach CDF Run 1 Analysis Charged Particle Df Correlations PT > PTmin |h|

Traditional Approach CDF Run 1 Analysis Charged Particle Df Correlations PT > PTmin |h| < hcut “Transverse” region very sensitive to the “underlying event”! Leading Calorimeter Jet or Leading Charged Particle or Z-Boson Æ Look at charged particle correlations in the azimuthal angle Df relative to a leading object (i. e. Calo. Jet#1, Chg. Jet#1, PTmax, Z-boson). For CDF PTmin = 0. 5 Ge. V/c hcut = 1. Æ Define |Df| < 60 o as “Toward”, 60 o < |Df| < 120 o as “Transverse”, and |Df| > 120 o as “Away”. Æ All three regions have the same area in h-f space, Dh×Df = 2 hcut× 120 o = 2 hcut× 2 p/3. Construct densities by dividing by the area in h-f space. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 10

Tevatron Energy Scan 900 Ge. V 300 1. 96 Te. V Æ Just before

Tevatron Energy Scan 900 Ge. V 300 1. 96 Te. V Æ Just before the shutdown of the Tevatron CDF has collected more than 10 M “min-bias” events at several center-of-mass energies! 300 Ge. V 12. 1 M MB Events 900 Ge. V 54. 3 M MB Events HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 11

Jet Observables Æ “Toward” Charged Particle Density: Number of charged particles (p. T >

Jet Observables Æ “Toward” Charged Particle Density: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the “toward” region (not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “Toward” Charged PTsum Density: Scalar p. T sum of the charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the “toward” region (not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “Away” Charged Particle Density: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the “away” region as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “Away” Charged PTsum Density: Scalar p. T sum of the charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the “away” region as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut = 0. 8 HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 12

UE Observables Æ “Transverse” Charged Particle Density: Number of charged particles (p. T >

UE Observables Æ “Transverse” Charged Particle Density: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < hcut) in the “transverse” region as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “Transverse” Charged PTsum Density: Scalar p. T sum of the charged particles (p. T > 0. 5 Ge. V/c, |h| < hcut) in the “transverse” region as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/3, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “Transverse” Charged Particle Average PT: Event-by-event <p. T> = PTsum/Nchg for charged particles (p. T > 0. 5 Ge. V/c, |h| < hcut) in the “transverse” region as defined by the leading charged particle, PTmax, averaged over all events with at least one particle in the “transverse” region with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ Zero “Transverse” Charged Particles: If there are no charged particles in the “transverse” region then Nchg and PTsum are zero and one includes these zeros in the average over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. However, if there are no charged particles in the “transverse” region the event is not used in constructing the “transverse” average p. T. hcut = 0. 8 HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 13

Observables Æ Total Number of Charged Particles: Number of charged particles (p. T >

Observables Æ Total Number of Charged Particles: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8, including PTmax) as defined by the leading charged particle, PTmax, with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ Overall “Associated” Charged Particle Density: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8, not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ Overall “Associated” Charged PTsum Density: Scalar p. T sum of the charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8, not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut = 0. 8 Note: The overall “associated” density is equal to the average of the “Towards”, “Away”, and “Transverse” densities. Overall “Associated” Density = (“Towards” Density + “Away” Density + “Transverse” Density)/3 HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 14

UE Observables Æ “trans. MAX” and “trans. MIN” Charged Particle Density: Number of charged

UE Observables Æ “trans. MAX” and “trans. MIN” Charged Particle Density: Number of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the maximum (minimum) of the two “transverse” regions as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/6, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Æ “trans. MAX” and “trans. MIN” Charged PTsum Density: Scalar p. T sum of charged particles (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in the maximum (minimum) of the two “transverse” regions as defined by the leading charged particle, PTmax, divided by the area in h-f space, 2 hcut× 2 p/6, averaged over all events with at least one particle with p. T > 0. 5 Ge. V/c, |h| < hcut. Overall “Transverse” = “trans. MAX” + “trans. MIN” hcut = 0. 8 Note: The overall “transverse” density is equal to the average of the “trans. MAX” and “Trans. MIN” densities. The “Trans. DIF” Density is the “trans. MAX” Density minus the “trans. MIN” Density “Transverse” Density = “trans. AVE” Density = (“trans. MAX” Density + “trans. MIN” Density)/2 “Trans. DIF” Density = “trans. MAX” Density - “trans. MIN” Density HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 15

“trans. MIN” & “trans. DIF” Æ The “toward” region contains the leading “jet”, while

“trans. MIN” & “trans. DIF” Æ The “toward” region contains the leading “jet”, while the “away” region, on the average, contains the “away-side” “jet”. The “transverse” region is perpendicular to the plane of the hard 2 -to-2 scattering and is very sensitive to the “underlying event”. For events with large initial or final-state radiation the “trans. MAX” region defined contains the third jet while both the “trans. MAX” and “trans. MIN” regions receive contributions from the MPI and beam remnants. Thus, the “trans. MIN” region is very sensitive to the multiple parton interactions (MPI) and beam-beam remnants (BBR), while the “trans. MAX” minus the “trans. MIN” (i. e. “trans. DIF”) is very sensitive to initial-state radiation (ISR) and final -state radiation (FSR). “Trans. MIN” density more sensitive to MPI & BBR. “Trans. DIF” density more sensitive to ISR & FSR. 0 ≤ “Trans. DIF” ≤ 2×”Trans. AVE” “Trans. DIF” = “Trans. AVE” if “Trans. MIX” = 3×”Trans. MIN” HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 16

PTmax UE Data Æ CDF PTmax UE Analysis: “Towards”, “Away”, “trans. MAX”, “trans. MIN”,

PTmax UE Data Æ CDF PTmax UE Analysis: “Towards”, “Away”, “trans. MAX”, “trans. MIN”, “trans. AVE”, and “trans. DIF” charged particle and PTsum densities (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in proton-antiproton collisions at 300 Ge. V, 900 Ge. V, and 1. 96 Te. V (R. Field analysis). Æ CMS PTmax UE Analysis: “Towards”, “Away”, “trans. MAX”, “trans. MIN”, “trans. AVE”, and “trans. DIF” charged particle and PTsum densities (p. T > 0. 5 Ge. V/c, |h| < 0. 8) in proton-proton collisions at 900 Ge. V and 7 Te. V (Mohammed Zakaria Ph. D. Thesis, CMS PAS FSQ-12 -020). Æ CMS UE Tunes: PYTHIA 6. 4 Tune Z 1 (CTEQ 5 L) and PYTHIA 6. 4 Tune Z 2* (CTEQ 6 L) and PYTHIA 8 Tune 4 C* (CTEQ 6 L). All 3 were tuned to the CMS leading chgjet “trans. AVE” UE data at 900 Ge. V and 7 Te. V. Similar to Tune 4 C by Corke and Sjöstrand! HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 17

MB&UE Working Group MB & UE Common Plots CMS ATLAS ÆThe LPCC MB&UE Working

MB&UE Working Group MB & UE Common Plots CMS ATLAS ÆThe LPCC MB&UE Working Group has suggested several MB&UE “Common Plots” the all the LHC groups can produce and compare with each other. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 18

CMS Common Plots Observable 900 Ge. V 7 Te. V MB 1: d. Nchg/dh

CMS Common Plots Observable 900 Ge. V 7 Te. V MB 1: d. Nchg/dh Nchg ≥ 1 |h| < 0. 8 p. T > 0. 5 Gev/c & 1. 0 Ge. V/c Done QCD-10 -024 Stalled MB 2: d. Nchg/dp. T Nchg ≥ 1 |h| < 0. 8 that all the “common plots” require MB 3: Multiplicity. Note Distribution Stalled one charged particle with Stalled |h| < 0. 8 p. T > 0. 5 Ge. V/cat&least 1. 0 Ge. V/c p > 0. 5 Ge. V/c and |h| < 0. 8! MB 4: <p. T> versus Nchg T In progress This done so that the plots are |h| < 0. 8 p. T > 0. 5 Ge. V/c & 1. 0 Ge. V/c (Antwerp) In progress (Antwerp) UE 1: Transverse Nchg & PTsum as defined by the leading charged particle, PTmax |h| < 0. 8 p. T > 0. 5 Ge. V/c & 1. 0 Ge. V/c Done FSQ-12 -020 less sensitive to SD and DD. Done FSQ-12 -020 Direct charged particles (including leptons) corrected to the particle level with no corrections for SD or DD. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 19

MB Common Plots 7 Te. V Direct charged particles (including leptons) corrected to the

MB Common Plots 7 Te. V Direct charged particles (including leptons) corrected to the particle level with no corrections for SD or DD. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 20

CDF Common Plots Observable 300 Ge. V 900 Ge. V 1. 96 Te. V

CDF Common Plots Observable 300 Ge. V 900 Ge. V 1. 96 Te. V Done MB 2: d. Nchg/dp. T Nchg ≥ 1 |h| < 0. 8 In progress MB 3: Multiplicity Distribution |h| < 0. 8 p. T > 0. 5 Ge. V/c & 1. 0 Ge. V/c In progress MB 4: <p. T> versus Nchg |h| < 0. 8 p. T > 0. 5 Ge. V/c & 1. 0 Ge. V/c In progress MB 1: d. Nchg/dh Nchg ≥ 1 |h| < 0. 8 p. T > 0. 5 Gev/c & 1. 0 Ge. V/c UE 1: Transverse Nchg & PTsum as defined by the leading charged particle, PTmax |h| < 0. 8 p. T > 0. 5 Ge. V/c & 1. 0 Ge. V/c p. T > 0. 5 Ge. V/c Done Direct charged particles (including leptons) corrected to the particle level with no corrections for SD or DD. R. Field, C. Group, and D. Wilson. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 21

MB Common Plots 900 Ge. V Direct charged particles (including leptons) corrected to the

MB Common Plots 900 Ge. V Direct charged particles (including leptons) corrected to the particle level with no corrections for SD or DD. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 22

New CDF MB Data CMS CDF CDF Æ New Corrected CDF data at 300

New CDF MB Data CMS CDF CDF Æ New Corrected CDF data at 300 Ge. V, 900 Ge. V, and 1. 96 Te. V on on pseudo-rapidity distribution of charged particles, d. N/dh, with p. T > 0. 5 Ge. V/c. Events are required to have at least one charged particle with |h| < 0. 8 and p. T > 0. 5 Ge. V/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 23

New CDF MB Data CMS CDF CDF Æ New Corrected CDF data at 300

New CDF MB Data CMS CDF CDF Æ New Corrected CDF data at 300 Ge. V, 900 Ge. V, and 1. 96 Te. V on on pseudo-rapidity distribution of charged particles, d. N/dh, with p. T > 1. 0 Ge. V/c. Events are required to have at least one charged particle with |h| < 0. 8 and p. T > 1. 0 Ge. V/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 24

Energy Dependence d. N/dh Æ CMS data at 7 Te. V and 900 Ge.

Energy Dependence d. N/dh Æ CMS data at 7 Te. V and 900 Ge. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on d. N/dh at h = 0 with p. T > 0. 5 Ge. V/c as a function of the center-of-mass energy. Events are required to have at least one charged particle with |h| < 0. 8 and p. T > 0. 5 Ge. V/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 25

Energy Dependence d. N/dh Æ CMS data at 7 Te. V and 900 Ge.

Energy Dependence d. N/dh Æ CMS data at 7 Te. V and 900 Ge. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on d. N/dh at h = 0 with p. T > 1. 0 Ge. V/c as a function of the center-of-mass energy. Events are required to have at least one charged particle with |h| < 0. 8 and p. T > 1. 0 Ge. V/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 26

Total Number of Charged Particles <Nchg> = 4. 8! Æ CDF and CMS data

Total Number of Charged Particles <Nchg> = 4. 8! Æ CDF and CMS data on the pseudo-rapidity Æ CDF and CMS data total number of charged distribution, d. N/dh, for charged with p. T > 0. 5 particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 for events with at least one charged particle with p. T > 0. 5 Ge. V/c and |h| < 0. 8 plotted versus the centerof-mass energy (log scale). The data are corrected to the particle level with errors that include both Ecm Nchg error Nchg. Den error the statistical error and the systematic 300 Ge. V 2. 241 0. 175 0. 223 0. 017 uncertainty. 900 Ge. V 3. 012 0. 203 0. 300 0. 020 1. 96 Te. V 3. 439 0. 186 0. 342 0. 019 7 Te. V 4. 782 0. 063 0. 476 0. 006 HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 27

Total Number of Charged Particles Factor of 2. 1 increase! Æ CDF and CMS

Total Number of Charged Particles Factor of 2. 1 increase! Æ CDF and CMS data total number of charged Æ CDF and CMS data ratio of the total number of particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 for charged particles with p. T > 0. 5 Ge. V/c and |h| < events with at least one charged particle with p. T >0. 8 for events with at least one charged particle 0. 5 Ge. V/c and |h| < 0. 8 plotted versus the center- with p. T > 0. 5 Ge. V/c and |h| < 0. 8 plotted versus of-mass energy (log scale). The data are corrected the center-of-mass energy (log scale). The data to the particle level with errors that include both are divided by the value at 300 Ge. V. the statistical error and the systematic uncertainty. The data are compared with PYTHIA 6. 4 Tune Z 1 HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 28

Total Number of Charged Particles Æ CDF data at 1. 96 Te. V, 900

Total Number of Charged Particles Æ CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the total number of charged particles (including PTmax) as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 29

Total Number of Charged Particles Æ CMS and CDF data on the total number

Total Number of Charged Particles Æ CMS and CDF data on the total number of charged particles (including PTmax) as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 30

“Associated” Charged Particle Density Æ Corrected CDF data at 1. 96 Te. V, 900

“Associated” Charged Particle Density Æ Corrected CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the “associated” charged particle density in the “toward”, “away”, and “transverse” regions as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 31

“Toward” Associated Density 300 Ge. V “Away” Parton “Toward” Parton “PTmax” Particle “Associated” Toward

“Toward” Associated Density 300 Ge. V “Away” Parton “Toward” Parton “PTmax” Particle “Associated” Toward Particles “Away” Particles Æ At low center-of-mass energies PTmax carries almost all the momentum of the “toward” parton (i. e. z ≈ 1) leaving very little momentum for the other particles in the “jet”. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 32

“Toward” Associated Density 1. 96 Te. V “Away” Parton “Toward” Parton “PTmax” Particle “Associated”

“Toward” Associated Density 1. 96 Te. V “Away” Parton “Toward” Parton “PTmax” Particle “Associated” Toward Particles “Away” Particles Æ At higher center-of-mass energies the same PTmax carries less of the momentum of the “toward” parton (i. e. z < 1) leaving more momentum for the other particles in the “jet”. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 33

“Transverse” Charge Particle Fraction Æ CMS and CDF data on the fraction of charged

“Transverse” Charge Particle Fraction Æ CMS and CDF data on the fraction of charged particle in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The plot shows the “transverse” Nchg divided by the total Nchg. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 34

“Associated” Charged Particle Density Æ Corrected CDF data at 1. 96 Te. V, 900

“Associated” Charged Particle Density Æ Corrected CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the “associated” charged particle density in the “toward”, “away”, and “transverse” regions as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 35

“Associated” Charged PTsum Density Æ Corrected CDF data at 1. 96 Te. V, 900

“Associated” Charged PTsum Density Æ Corrected CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the “associated” charged PTsum density in the “toward”, “away”, and “transverse” regions as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 36

UE Common Plots HEP Seminar - Baylor Waco, January 21, 2014 Rick Field –

UE Common Plots HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 37

LHC CDF versus CMS Æ CDF and CMS data at 900 Ge. V/c on

LHC CDF versus CMS Æ CDF and CMS data at 900 Ge. V/c on the charged PTsum density in the “transverse” charged particle density in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 38

“Trans. AVE” Density Æ Corrected CMS data at 7 Te. V and CDF data

“Trans. AVE” Density Æ Corrected CMS data at 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. AVE” charged PTsum density in the “trans. AVE” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 39

“Trans. AVE” vs Ecm Æ Corrected CMS data at 900 Ge. V and 7

“Trans. AVE” vs Ecm Æ Corrected CMS data at 900 Ge. V and 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. AVE” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 Ge. V/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6. 4 Tune Z 1 and Tune Z 2*. Æ Corrected CMS data at 900 Ge. V and 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged PTsum density in the “trans. AVE” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 Ge. V/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6. 4 Tune Z 1 and Tune Z 2*. The data are “normalized” by dividing by the corresponding value at 300 Ge. V. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 40

MB versus the UE Æ Corrected CDF data on the charged particle density, in

MB versus the UE Æ Corrected CDF data on the charged particle density, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty and are compared with the overall charged particle density (straight lines). HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 41

MB versus the UE Æ Corrected CDF and CMS data on the overall density

MB versus the UE Æ Corrected CDF and CMS data on the overall density of charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 for events with at least one charged particle with p. T > 0. 5 Ge. V/c and |h| < 0. 8 and on the charged particle density, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 Ge. V/c. The data are plotted versus the center-of-mass energy (log scale). HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS Amazing! 42

“Transverse”/Overall Amazing! The “trans. AVE” = “transverse” density increases faster with center-of-mass energy than

“Transverse”/Overall Amazing! The “trans. AVE” = “transverse” density increases faster with center-of-mass energy than the overall density (Nchg ≥ 1)! Æ Corrected CDF and CMS data on the charged particle density ratio, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 for particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. 5 < PTmax < 6 Ge. V/c. The ratio corresponds to the “transverse” charged particle density divided by the overall charged particle density (Nchg ≥ 1). The data are plotted versus the center-of-mass energy (log scale). HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 43

“trans. MAX/MIN” Nchg. Den Æ Corrected CDF data at 1. 96 Te. V, 900

“trans. MAX/MIN” Nchg. Den Æ Corrected CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. MAX” and “trans. MIN” regions as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA 6. 4 Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 44

“tran. MIN” Nchg Fraction Æ CMS and CDF data on the fraction of charged

“tran. MIN” Nchg Fraction Æ CMS and CDF data on the fraction of charged particles in the “trans. MIN” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The plot shows “trans. MIN” Nchg divided by the overall “transverse” Nchg. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 45

“trans. MAX/MIN” Nchg. Den Æ Corrected CMS data at 7 Te. V and CDF

“trans. MAX/MIN” Nchg. Den Æ Corrected CMS data at 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. MAX” charged particle density in the “trans. MIN” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 46

“trans. DIF/AVE” Nchg. Den Æ Corrected CMS data at 7 Te. V and CDF

“trans. DIF/AVE” Nchg. Den Æ Corrected CMS data at 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. DIF” charged particle density in the “trans. AVE” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 47

“trans. MAX” Nchg. Den vs Ecm Æ Corrected CMS data at 7 Te. V

“trans. MAX” Nchg. Den vs Ecm Æ Corrected CMS data at 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the charged particle density in the “trans. MAX” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty. HEP Seminar - Baylor Waco, January 21, 2014 Æ Corrected CMS and CDF data on the charged particle density in the “trans. MAX” region as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 Ge. V/c. The data are plotted versus the center-of-mass energy (log scale). Rick Field – Florida/CDF/CMS 48

“Transverse” Nchg. Den vs Ecm <trans. MIN> = 4. 7 <trans. MAX> = 2.

“Transverse” Nchg. Den vs Ecm <trans. MIN> = 4. 7 <trans. MAX> = 2. 7 Æ Corrected CMS data at 7 Te. V and CDF data Æ Ratio of CMS data at 7 Te. V and CDF data at at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the 1. 96 Te. V, 900 Ge. V, and 300 Ge. V to the value charged particle density in the “trans. MAX” at 300 Ge. V for the charged particle density in and “trans. MIN” regions as defined by the “trans. MAX” and “trans. MIN” regions as leading charged particle (PTmax) for charged defined by the leading charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 (PTmax) for charged particles with p. T > 0. 5 with 5 < PTmax < 6 Ge. V/c. The data are Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 plotted versus the center-of-mass energy (log Ge. V/c. The data are plotted versus the center scale). -of-mass energy (log scale). The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 49

“Transverse” Nchg. Den vs Ecm <trans. AVE> = 3. 1 <trans. DIF> = 2.

“Transverse” Nchg. Den vs Ecm <trans. AVE> = 3. 1 <trans. DIF> = 2. 2 Æ Corrected CMS data at 7 Te. V and CDF data Æ Ratio of CMS data at 7 Te. V and CDF data at at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V on the 1. 96 Te. V, 900 Ge. V, and 300 Ge. V to the value charged particle density in the “trans. AVE” at 300 Ge. V for the charged particle density in and “trans. DIF” regions as defined by the “trans. AVE” and “trans. DIF” regions as leading charged particle (PTmax) for charged defined by the leading charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 (PTmax) for charged particles with p. T > 0. 5 with 5 < PTmax < 6 Ge. V/c. The data are Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 plotted versus the center-of-mass energy (log Ge. V/c. The data are plotted versus the center scale). -of-mass energy (log scale). The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 50

“Trans. MIN/DIF” vs Ecm <trans. MIN> = 5. 7 <trans. MIN> = 4. 7

“Trans. MIN/DIF” vs Ecm <trans. MIN> = 5. 7 <trans. MIN> = 4. 7 <trans. DIF> = 2. 2 <trans. DIF> = 2. 6 The “trans. MIN” (MPI-BBR component) increases much faster with center-of-mass energy than the “trans. DIF” (ISR-FSR component)! Æ Ratio of CMS data at 7 Te. V and CDF data at. Duh!! Æ Ratio of CMS data at 7 Te. V and CDF data at 1. 96 Te. V, 900 Ge. V, and 300 Ge. V to the value at 300 Ge. V for the charged particle density in at 300 Ge. V for the charged PTsum density in the “trans. MIN”, and “trans. DIF” regions as defined by the leading charged particle (PTmax) for charged particles with p. T > 0. 5 Ge. V/c and |h| < 0. 8 with 5 < PTmax < 6 Ge. V/c. The data are plotted versus the center -of-mass energy (log scale). The data are compared with PYTHIA Tune Z 1 and Tune Z 2*. HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 51

“Tevatron” to the LHC CMS CDF CDF Tune Z 2* & 4 C* HEP

“Tevatron” to the LHC CMS CDF CDF Tune Z 2* & 4 C* HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 52

“Tevatron” to the LHC CMS CDF Tune Z 2* & 4 C* HEP Seminar

“Tevatron” to the LHC CMS CDF Tune Z 2* & 4 C* HEP Seminar - Baylor Waco, January 21, 2014 CDF Rick Field – Florida/CDF/CMS 53

Summary & Conclusions ÆThe “transverse” density increases faster with center-of-mass energy than the overall

Summary & Conclusions ÆThe “transverse” density increases faster with center-of-mass energy than the overall density (Nchg ≥ 1)! However, the “transverse” = “trans. AVE” region is not a true measure of the energy dependence of MPI since it receives large contributions from ISR and FSR. ÆThe “trans. MIN” (MPI-BBR component) increases much faster with center. What we are learning should of-mass energy than for the “trans. DIF” (ISR-FSR component)! allow a deeper understanding of MPIPreviously we only knew the energy dependence of “trans. AVE”. which will result in more precise ÆPYTHIA 6. 4 Tune Z 1 & Z 2* and PYTHIA Tune 4 C* do a fairly good job predictions at the 8 future in describing the energy of the however is room for LHCdeperdence energies of 13 UE, & 14 Te. V! there e improvement! The parameterization PT 0(Ecm) = PT 0(Ecm/E 0) seems to work! We now have at lot of MB & UE data at 300 Ge. V, 900 Ge. V, 1. 96 Te. V, and 7 Te. V! We can study the energy dependence more precisely than ever before! HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMS 54