HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMSPage 1 Outline of Talk CMS...

HEP Seminar - Baylor Waco, January 21, 2014

Rick Field – Florida/CDF/CMS

Outline of Talk

CMS at the LHCCDF Run 2

300 GeV, 900 GeV, 1.96 TeV900 GeV, 7 & 8 TeV

HEP SeminarHEP Seminar

CDF data from the Tevatron Energy Scan.

The “transMAX”, “transMIN”, “transAVE” and “transDIF” UE observables.

The overall event topology for events with at least 1 charged particle.

Summary & Conclusions.

Mapping out the energy dependence: Tevatron to the LHC!

Comparisions with PYTHIA 6.4 Tune Z1 & Z2* and PYTHIA 8 Tune 4C*.

Rick FieldUniversity of Florida

Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton

Underlying Event Underlying Event

Initial-State Radiation

Final-State Radiation

Tevatron Energy Scan: Findings & Surprises



QCD Monte-Carlo Models:QCD Monte-Carlo Models:High Transverse Momentum JetsHigh Transverse Momentum Jets

Start with the perturbative 2-to-2 (or sometimes 2-to-3) parton-parton scattering and add initial and final-state gluon radiation (in the leading log approximation or modified leading log approximation).

Hard Scattering

PT(hard)

Outgoing Parton

Outgoing Parton



Hard Scattering

PT(hard)

Outgoing Parton

Outgoing Parton



Proton AntiProton


Proton AntiProton


“Hard Scattering” Component

“Jet”

“Jet”

“Underlying Event”

The “underlying event” consists of the “beam-beam remnants” and from particles arising from soft or semi-soft multiple parton interactions (MPI).

Of course the outgoing colored partons fragment into hadron “jet” and inevitably “underlying event” observables receive contributions from initial and final-state radiation.

“Jet”

The “underlying event” is an unavoidable background to most collider observables and having good understand of it leads to

more precise collider measurements!



Proton-Proton CollisionsProton-Proton Collisions Elastic Scattering Single Diffraction

M

tot = ELSD DD HC

Double Diffraction

M1 M2

Proton Proton

“Soft” Hard Core (no hard scattering)

Proton Proton

PT(hard)

Outgoing Parton

Outgoing Parton




“Hard” Hard Core (hard scattering)

Hard Core The “hard core” component

contains both “hard” and “soft” collisions.

“Inelastic Non-Diffractive Component”

NDtot = ELIN



The Inelastic Non-Diffractive The Inelastic Non-Diffractive Cross-SectionCross-Section

Proton Proton

Proton Proton +

Proton Proton

Proton Proton

+

Proton Proton +

+ …

“Semi-hard” parton-parton collision(pT < ≈2 GeV/c)

Occasionally one of the parton-parton collisions is hard(pT > ≈2 GeV/c)

Majority of “min-bias” events!

Multiple-parton interactions (MPI)!



The “Underlying Event”The “Underlying Event”

Proton Proton

Select inelastic non-diffractive events that contain a hard scattering

Proton Proton

Proton Proton +

Proton Proton

+ + …


Hard parton-parton collisions is hard(pT > ≈2 GeV/c) The “underlying-event” (UE)!


Given that you have one hard scattering it is more probable to have MPI! Hence, the UE has more activity than “min-bias”.

1/(pT)4→ 1/(pT2+pT0

2)2



Model of Model of NDND

Proton Proton

Proton Proton +

Proton Proton

Proton Proton

+

Proton Proton +

+ …


Allow leading hard scattering to go to zero pT with same cut-off as the MPI!

Model of the inelastic non-diffractive cross section!


Proton Proton

1/(pT)4→ 1/(pT2+pT0

2)2



UE TunesUE Tunes

Proton Proton

Proton Proton +

Proton Proton

Proton Proton

+

Proton Proton +

+ …


“Min-Bias” (ND)

Fit the “underlying event” in a hard

scattering process.

Predict MB (ND)!

1/(pT)4→ 1/(pT2+pT0

2)2

Allow primary hard-scattering to go to pT = 0 with same cut-off!

Single Diffraction

M

Double Diffraction

M1 M2

“Min-Bias” (add single & double diffraction)

Predict MB (IN)!

All of Rick’s tunes (except X2):A, AW, AWT,DW, DWT,

D6, D6T, CW, X1, and Tune Z1,are UE tunes!



MB TunesMB Tunes

Proton Proton +

Proton Proton

Proton Proton

+

Proton Proton +

+ …


“Min-Bias” (ND)

Predict the “underlying event” in a hard

scattering process!

Fit MB (ND).

Proton Proton

Most of Peter Skand’s tunes:S320 Perugia 0, S325 Perugia X,

S326 Perugia 6are MB tunes!



Parameter Default

Description

PARP(83) 0.5 Double-Gaussian: Fraction of total hadronic matter within PARP(84)

PARP(84) 0.2 Double-Gaussian: Fraction of the overall hadron radius containing the fraction PARP(83) of the total hadronic matter.

PARP(85) 0.33 Probability that the MPI produces two gluons with color connections to the “nearest neighbors.

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.

PARP(89) 1 TeV Determines the reference energy E0.

PARP(82) 1.9 GeV/c

The cut-off PT0 that regulates the 2-to-2 scattering divergence 1/PT4→1/(PT2+PT0

2)2

PARP(90) 0.16 Determines the energy dependence of the cut-off

PT0 as follows PT0(Ecm) = PT0(Ecm/E0) with = 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 initial-state radiation.

Hard Core

Multiple Parton Interaction

Color String

Color String

Multiple Parton Interaction

Color String

Hard-Scattering Cut-Off PT0

1

2

3

4

5

100 1,000 10,000 100,000

CM Energy W (GeV)P

T0

(G

eV

/c)

PYTHIA 6.206

= 0.16 (default)

= 0.25 (Set A))

Take E0 = 1.8 TeV

Reference pointat 1.8 TeV

Determine by comparingwith 630 GeV data!

Affects the amount ofinitial-state radiation!

Tuning PYTHIA 6.2:Tuning PYTHIA 6.2:Multiple Parton Interaction ParametersMultiple Parton Interaction Parameters

Determines the energy dependence of the MPI!Remember the energy dependence

of the “underlying event”activity depends on both the = PARP(90) and the PDF!



Traditional ApproachTraditional Approach

Look at charged particle correlations in the azimuthal angle relative to a leading object (i.e. CaloJet#1, ChgJet#1, PTmax, Z-boson). For CDF PTmin = 0.5 GeV/c cut = 1.

Charged Particle Correlations PT > PTmin || < cut

Leading Object Direction

“Toward”

“Transverse” “Transverse”

“Away”

Define || < 60o as “Toward”, 60o < || < 120o as “Transverse”, and || > 120o as “Away”.

Leading Calorimeter Jet or Leading Charged Particle Jet or

Leading Charged Particle orZ-Boson

-cut +cut

2

0

Leading Object

Toward Region

Transverse Region

Transverse Region

Away Region

Away Region

All three regions have the same area in - space, × = 2cut×120o = 2cut×2/3. Construct densities by dividing by the area in - space.

Charged Jet #1Direction


“Toward”

“Away”

“Toward-Side” Jet

“Away-Side” Jet

“Transverse” region very sensitive to the “underlying event”!

CDF Run 1 Analysis



Tevatron Energy ScanTevatron Energy Scan

Just before the shutdown of the Tevatron CDF has collected more than 10M “min-bias” events at several center-of-mass energies!

Proton

AntiProton

1 mile CDF

Proton AntiProton 1.96 TeV300 GeV

300 GeV 12.1M MB Events

900 GeV 54.3M MB Events

900 GeV



Jet ObservablesJet Observables“Toward” Charged Particle Density: Number of charged particles (pT

> 0.5 GeV/c, || < 0.8) in the “toward” region (not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

PTmax Direction

“Toward”


“Away”

“Toward” Charged PTsum Density: Scalar pT sum of the charged particles (pT > 0.5 GeV/c, || < 0.8) in the “toward” region (not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

“Away” Charged Particle Density: Number of charged particles (pT > 0.5 GeV/c, || < 0.8) in the “away” region as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

“Away” Charged PTsum Density: Scalar pT sum of the charged particles (pT > 0.5 GeV/c, || < 0.8) in the “away” region as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

cut = 0.8



UE ObservablesUE Observables“Transverse” Charged Particle Density: Number of charged particles

(pT > 0.5 GeV/c, || < cut) in the “transverse” region as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

PTmax Direction

“Toward”


“Away”

“Transverse” Charged PTsum Density: Scalar pT sum of the charged particles (pT > 0.5 GeV/c, || < cut) in the “transverse” region as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/3, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

“Transverse” Charged Particle Average PT: Event-by-event <pT> = PTsum/Nchg for charged particles (pT > 0.5 GeV/c, || < cut) 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 pT > 0.5 GeV/c, || < cut.

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 pT > 0.5 GeV/c, || < cut. However, if there are no charged particles in the “transverse” region then the event is not used in constructing the “transverse” average pT.

cut = 0.8



ObservablesObservables

Overall “Associated” Charged Particle Density: Number of charged particles (pT > 0.5 GeV/c, || < 0.8, not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

PTmax Direction

“Toward”


“Away”

Overall “Associated” Charged PTsum Density: Scalar pT sum of the charged particles (pT > 0.5 GeV/c, || < 0.8, not including PTmax) as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

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

cut = 0.8

Total Number of Charged Particles: Number of charged particles (pT > 0.5 GeV/c, || < 0.8, including PTmax) as defined by the leading charged particle, PTmax, with at least one particle with pT > 0.5 GeV/c, || < cut.



UE ObservablesUE Observables“transMAX” and “transMIN” Charged Particle Density: Number of

charged particles (pT > 0.5 GeV/c, || < 0.8) in the the maximum (minimum) of the two “transverse” regions as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/6, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

PTmax Direction

“Toward”

“TransMAX” “TransMIN”

“Away”

“transMAX” and “transMIN” Charged PTsum Density: Scalar pT sum of charged particles (pT > 0.5 GeV/c, || < 0.8) in the the maximum (minimum) of the two “transverse” regions as defined by the leading charged particle, PTmax, divided by the area in - space, 2cut×2/6, averaged over all events with at least one particle with pT > 0.5 GeV/c, || < cut.

Note: The overall “transverse” density is equal to the average of the “transMAX” and “TransMIN” densities. The “TransDIF” Density is the “transMAX” Density minus the “transMIN” Density

“Transverse” Density = “transAVE” Density = (“transMAX” Density + “transMIN” Density)/2

“TransDIF” Density = “transMAX” Density - “transMIN” Density

cut = 0.8Overall “Transverse” = “transMAX” + “transMIN”



““transMIN” & “transDIF”transMIN” & “transDIF”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 “transMAX” region defined contains the third jet while both the “transMAX” and “transMIN” regions receive contributions from the MPI and beam-beam remnants. Thus, the “transMIN” region is very sensitive to the multiple parton interactions (MPI) and beam-beam remnants (BBR), while the “transMAX” minus the “transMIN” (i.e. “transDIF”) is very sensitive to initial-state radiation (ISR) and final-state radiation (FSR).

“TransDIF” density more sensitive to ISR & FSR.

PTmax Direction


“Toward”

“Away”

“Toward-Side” Jet

“Away-Side” Jet

Jet #3

“TransMIN” density more sensitive to MPI & BBR.

0 ≤ “TransDIF” ≤ 2×”TransAVE”

“TransDIF” = “TransAVE” if “TransMIX” = 3×”TransMIN”



PTmax UE DataPTmax UE DataCDF PTmax UE Analysis: “Towards”, “Away”, “transMAX”,

“transMIN”, “transAVE”, and “transDIF” charged particle and PTsum densities (pT > 0.5 GeV/c, || < 0.8) in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV (R. Field analysis).

PTmax Direction

“Toward”


“Away”

CMS PTmax UE Analysis: “Towards”, “Away”, “transMAX”, “transMIN”, “transAVE”, and “transDIF” charged particle and PTsum densities (pT > 0.5 GeV/c, || < 0.8) in proton-proton collisions at 900 GeV and 7 TeV (Mohammed Zakaria Ph.D. Thesis, CMS PAS FSQ-12-020).

CMS UE Tunes: PYTHIA 6.4 Tune Z1 (CTEQ5L) and PYTHIA 6.4 Tune Z2* (CTEQ6L) and PYTHIA 8 Tune 4C* (CTEQ6L). All 3 were tuned to the CMS leading chgjet “transAVE” UE data at 900 GeV and 7 TeV.

Similar to Tune 4C by Corke and Sjöstrand!



MB&UE Working Group

CMS

ATLAS

MB & UE Common Plots

The LPCC MB&UE Working Group has suggested several MB&UE “Common Plots” the all the LHC groups can produce and compare with each other.

Proton Proton

“Minimum Bias” Collisions

Proton Proton

PT(hard)

Outgoing Parton

Outgoing Parton






CMS Common PlotsCMS Common PlotsObservable 900 GeV 7 TeV

MB1: dNchg/d Nchg ≥ 1

|| < 0.8 pT > 0.5 Gev/c & 1.0 GeV/c

Done

QCD-10-024

Done

QCD-10-024

MB2: dNchg/dpT Nchg ≥ 1 || < 0.8 Stalled Stalled

MB3: Multiplicity Distribution

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/cStalled Stalled

MB4: <pT> versus Nchg

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/c

In progress

(Antwerp)

In progress

(Antwerp)

UE1: Transverse Nchg & PTsum as defined by the leading charged particle, PTmax

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/c

Done

FSQ-12-020

Done

FSQ-12-020

Direct charged particles (including leptons) corrected to the particle level with no corrections for SD or DD.

Note that all the “common plots” requireat least one charged particle with

pT > 0.5 GeV/c and || < 0.8!This done so that the plots are

less sensitive to SD and DD.



MB Common Plots 7 TeVMB Common Plots 7 TeV




CDF Common PlotsCDF Common PlotsObservable 300 GeV 900 GeV 1.96 TeV

MB1: dNchg/d Nchg ≥ 1

|| < 0.8 pT > 0.5 Gev/c & 1.0 GeV/cDone Done Done

MB2: dNchg/dpT Nchg ≥ 1 || < 0.8 In progress In progress In progress

MB3: Multiplicity Distribution

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/cIn progress In progress In progress

MB4: <pT> versus Nchg

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/cIn progress In progress In progress

UE1: Transverse Nchg & PTsum as defined by the leading charged particle, PTmax

|| < 0.8 pT > 0.5 GeV/c & 1.0 GeV/c

pT > 0.5 GeV/c

Done

pT > 0.5 GeV/c

Done

pT > 0.5 GeV/c

Done


R. Field, C. Group, and D. Wilson.



MB Common Plots 900 GeVMB Common Plots 900 GeV


Pseudo-Rapidity Distribution: dN/d

1.4

1.6

1.8

2.0

2.2

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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um

ber

RDF Preliminary Corrected Data

Charged Particles (||<0.8, PT>0.5 GeV/c)

900 GeV

At least 1 charged particle

CDF

CMS

ATLAS ALICE


0.95

1.00

1.05

1.10

1.15

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Av

erag

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ber



900 GeV


CDF

CMSATLASALICE



New CDF MB DataNew CDF MB DataPseudo-Rapidity Distribution: dN/d

0

1

2

3

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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1.96 TeV

300 GeV

900 GeV

CDF Preliminary Corrected Data



New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on on pseudo-rapidity distribution of charged particles, dN/d, with pT > 0.5 GeV/c. Events are required to have at least one charged particle with || < 0.8 and pT > 0.5 GeV/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


1.5

2.0

2.5

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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900 GeV


CDF

CMS


0

1

2

3

4

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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ber

1.96 TeV

300 GeV

900 GeV




7 TeV

Tune Z1

CDF

CDFCDF

CMS



New CDF MB DataNew CDF MB Data

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on on pseudo-rapidity distribution of charged particles, dN/d, with pT > 1.0 GeV/c. Events are required to have at least one charged particle with || < 0.8 and pT > 1.0 GeV/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


0.5

1.0

1.5

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

e N

um

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1.96 TeV

300 GeV

900 GeV





0.8

0.9

1.0

1.1

1.2

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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900 GeV


CDF

CMS


0.5

1.0

1.5

2.0

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Ave

rag

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1.96 TeV

300 GeV

900 GeV




7 TeV

Tune Z1

CDF

CDFCDF

CMS



Energy Dependence dN/dEnergy Dependence dN/d

CMS data at 7 TeV and 900 GeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on dN/d at = 0 with pT > 0.5 GeV/c as a function of the center-of-mass energy. Events are required to have at least one charged particle with || < 0.8 and pT > 0.5 GeV/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

Pseudo-Rapidity Distribution: dN/d(=0)

1.0

1.5

2.0

2.5

3.0

3.5

0.1 1.0 10.0

Center-of-Mass Energy (GeV)

Ave

rag

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um

ber




CDF black dotsCMS red squares


1.0

1.5

2.0

2.5

3.0

3.5

0.1 1.0 10.0


Ave

rag

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um

ber




Tune Z1




Energy Dependence dN/dEnergy Dependence dN/d

CMS data at 7 TeV and 900 GeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on dN/d at = 0 with pT > 1.0 GeV/c as a function of the center-of-mass energy. Events are required to have at least one charged particle with || < 0.8 and pT > 1.0 GeV/c. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


0.5

1.0

1.5

2.0

0.1 1.0 10.0


Ave

rag

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Tune Z1




Total Number of Charged Total Number of Charged ParticlesParticles

Ecm Nchg error NchgDen error

300 GeV 2.241 0.175 0.223 0.017

900 GeV 3.012 0.203 0.300 0.020

1.96 TeV 3.439 0.186 0.342 0.019

7 TeV 4.782 0.063 0.476 0.006

8.0

8.0

dd

dNNchg

CDF and CMS data on the pseudo-rapidity distribution, dN/d, for charged with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8.

CDF and CMS data total number of charged particles with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8 plotted versus the center-of-mass energy (log scale). The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


0

1

2

3

4

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0

Pseudo-Rapidity

Av

erag

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1.96 TeV

300 GeV

900 GeV




7 TeV

Number of Charged Particles

2

3

4

5

0.1 1.0 10.0

Center-of-Mass Energy (TeV)

Ave

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CMS red squaresCDF blue dots


<Nchg> = 4.8!




CDF and CMS data total number of charged particles with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8 plotted versus the center-of-mass energy (log scale). The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


2

3

4

5

0.1 1.0 10.0


Ave

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1.0

1.4

1.8

2.2

0.1 1.0 10.0


Rat

io





Divided by 300 GeV Value

CDF and CMS data ratio of the total number of charged particles with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8 plotted versus the center-of-mass energy (log scale). The data are divided by the value at 300 GeV.

Factor of 2.1 increase! Number of Charged Particles

2

3

4

5

0.1 1.0 10.0


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Generator Level Theory




Tune Z1


1.0

1.4

1.8

2.2

0.1 1.0 10.0


Rat

io







Tune Z1

The data are compared with PYTHIA 6.4 Tune Z1




CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the total number of charged particles (including PTmax) as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

Total Number of Charged Particles

0

3

6

9

12

0 5 10 15 20

PTmax (GeV/c)

Ave

rag

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1.96 TeV

<NchgTOT> = 3.44


0

3

6

9

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0 5 10 15 20

PTmax (GeV/c)

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900 GeV

<NchgTOT> = 3.01


0

2

4

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8

0 2 4 6 8 10 12 14

PTmax (GeV/c)

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300 GeV

<NchgTOT> = 2.24



0

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10

15

20

0 5 10 15 20 25 30

PTmax (GeV/c)

Ave

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CMS Preliminary Corrected Data


7 TeV

<NchgTOT> = 4.78




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 pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


0

5

10

15

20

0 5 10 15 20 25 30

PTmax (GeV/c)

Ave

rag

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1.96 TeV

300 GeV

900 GeV

7 TeVRDF Preliminary Corrected Data


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““Associated” Charged Particle DensityAssociated” Charged Particle Density

Corrected CDF data at 1.96 TeV, 900 GeV, and 300 GeV 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 pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

"Associated" Charged Particle Density: dN/dd

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CDF Preliminary corrected data

Tune Z1 generator level


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The data are compared with PYTHIA Tune Z1.



““Toward” Associated DensityToward” Associated Density

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”.

“Toward” Parton“Away” Parton

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“Associated” Toward Particles

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““Toward” Associated DensityToward” Associated Density

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”.

“Toward” Parton“Away” Parton

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“Associated” Toward Particles

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““Transverse” Charge Particle Fraction Transverse” Charge Particle Fraction

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 pT > 0.5 GeV/c and || < 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.

"Transverse" Fraction of Charged Particles

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““Associated” Charged Particle DensityAssociated” Charged Particle Density

Corrected CDF data at 1.96 TeV, 900 GeV, and 300 GeV 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 pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

"Toward" Charged Particle Density: dN/dd

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CDF PreliminaryCorrected Data 1.96 TeV

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"Transverse" Charged Particle Density: dN/dd

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CDF Preliminary Corrected Data 1.96 TeV

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““Associated” Charged PTsum DensityAssociated” Charged PTsum Density

Corrected CDF data at 1.96 TeV, 900 GeV, and 300 GeV 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 pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

"Toward" Charged PTsum Density: dPT/dd

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"Away" Charged PTsum Density: dPT/dd

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"Toward" Charged PTsum Density: dPT/dd

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"Away" Charged PTsum Density: dPT/dd

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UE Common PlotsUE Common Plots"Transverse" Charged Particle Density: dN/dd

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CDF versus CMSCDF versus CMS

CDF and CMS data at 900 GeV/c on the charged particle density in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

"TransAVE" Charged Particle Density: dN/dd

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CDF and CMS data at 900 GeV/c on the charged PTsum density in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


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““TransAVE” DensityTransAVE” Density

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transAVE” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.


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7 TeVRDF Preliminary

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Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged PTsum density in the “transAVE” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.



““TransAVE” vs ETransAVE” vs Ecmcm

Corrected CMS data at 900 GeV and 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transAVE” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6.4 Tune Z1 and Tune Z2*.

Corrected CMS data at 900 GeV and 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged PTsum density in the “transAVE” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6.4 Tune Z1 and Tune Z2*.

The data are “normalized” by dividing by the corresponding value at 300 GeV.


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"TransAVE" Charged Particle Density Ratio

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Corrected CDF data on the charged particle density, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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).


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MB versus the UEMB versus the UE

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Corrected CDF and CMS data on the overall density of charged particles with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8 and on the charged particle density, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).


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Amazing!



““Transverse”/OverallTransverse”/Overall"Transverse" Charged Particle Density Ratio

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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 pT > 0.5 GeV/c and || < 0.8. The ratio corresponds to the “transverse” charged particle density divided by the overall charged particle density (Nchg ≥ 1).

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 pT > 0.5 GeV/c and || < 0.8 for 5 < PTmax < 6 GeV/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).

Amazing!


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The “transAVE” = “transverse” density increasesfaster with center-of-mass energy than the overall density (Nchg ≥ 1)!



““transMAX/MIN” NchgDentransMAX/MIN” NchgDen

Corrected CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transMAX” and “transMIN” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.


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The data are compared with PYTHIA 6.4 Tune Z1 and Tune Z2*.


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““tranMIN” Nchg FractiontranMIN” Nchg Fraction

CMS and CDF data on the fraction of charged particles in the “transMIN” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The plot shows “transMIN” 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.


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Generator Level Theory Tune Z2* (solid lines)Tune Z1 (dashed lines)

Transverse/Total


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Generator Level Theory Tune Z2* (solid lines)Tune 4C* (dashed lines)

Transverse/Total



““transMAX/MIN” NchgDentransMAX/MIN” NchgDen

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transMAX” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.

"TransMAX" Charged Particle Density: dN/dd

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"TransMIN" Charged Particle Density: dN/dd

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7 TeVRDF Preliminary



Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transMIN” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.



““transDIF/AVE” NchgDentransDIF/AVE” NchgDen

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transAVE” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transDIF” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 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 Z1 and Tune Z2*.


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"TransDIF" Charged Particle Density: dN/dd

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““transMAX” NchgDen vs EtransMAX” NchgDen vs Ecmcm

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transMAX” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

Corrected CMS and CDF data on the charged particle density in the “transMAX” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).


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5.0 < PTmax < 6.0 GeV/c



““Transverse” NchgDen vs ETransverse” NchgDen vs Ecmcm

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transMAX” and “transMIN” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).

Ratio of CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged particle density in the “transMAX” and “transMIN” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).

The data are compared with PYTHIA Tune Z1 and Tune Z2*.


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5.0 < PTmax < 6.0 GeV/c



<transMIN> = 4.7

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““Transverse” NchgDen vs ETransverse” NchgDen vs Ecmcm

Corrected CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV on the charged particle density in the “transAVE” and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).

Ratio of CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged particle density in the “transAVE” and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).


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““TransMIN/DIF” vs ETransMIN/DIF” vs Ecmcm

Ratio of CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged particle density in the “transMIN”, and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).

Ratio of CMS data at 7 TeV and CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged PTsum density in the “transMIN”, and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale).


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<transMIN> = 4.7

<transDIF> = 2.2

<transMIN> = 5.7

<transDIF> = 2.6

The “transMIN” (MPI-BBR component) increasesmuch faster with center-of-mass energy

than the “transDIF” (ISR-FSR component)!Duh!!



““Tevatron” to the LHCTevatron” to the LHC

Tune Z2* & 4C*CDF

CDF

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CMS"TransAVE" Charged Particle Density: dN/dd

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““Tevatron” to the LHCTevatron” to the LHC

Tune Z2* & 4C*CDF

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CMS"TransAVE" Charged PTsum Density: dPT/dd

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Summary & ConclusionsSummary & Conclusions

The “transMIN” (MPI-BBR component) increases much faster with center-of-mass energy than the “transDIF” (ISR-FSR component)! Previously we only knew the energy dependence of “transAVE”.

The “transverse” density increases faster with center-of-mass energy than the overall density (Nchg ≥ 1)! However, the “transverse” = “transAVE” region is not a true measure of the energy dependence of MPI since it receives large contributions from ISR and FSR.

We now have at lot of MB & UE data at300 GeV, 900 GeV, 1.96 TeV, and 7 TeV!

We can study the energy dependence more precisely than ever before!

PYTHIA 6.4 Tune Z1 & Z2* and PYTHIA 8 Tune 4C* do a fairly good job in describing the energy deperdence of the UE, however there is room for improvement! The parameterization PT0(Ecm) = PT0(Ecm/E0) seems to work!

What we are learning shouldallow for a deeper understanding of MPI

which will result in more precisepredictions at the future

LHC energies of 13 & 14 TeV!

HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMSPage 1 Outline of Talk CMS...

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Transcript of HEP Seminar - Baylor Waco, January 21, 2014 Rick Field – Florida/CDF/CMSPage 1 Outline of Talk CMS...