qcd@lhc 2012

QCD@LHC 2012 MSU, August 23, 2012

Rick Field – Florida/CDF/CMS

Rick FieldUniversity of Florida

Outline of Talk

Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton

Underlying Event Underlying Event

Initial-State Radiation

Final-State Radiation

CMS at the LHC

CDF Run 2

CDF PYTHIA 6.2 Tevatron Tune A and Tune DW.

CMS PYTHIA 6.4 LHC Tune Z1.

300 GeV, 900 GeV, 1.96 TeV

900 GeV, 7 & 8 TeV

New UE data at 300 GeV, 900 GeV, and 1.96 TeV from the Tevatron Energy-Scan.

New comparisons with PYTHIA 6.4 Tune Z1.

Much more coming soon!

MSU August 20-23, 2012

LPCC MB&UE working group “common plots”.

Energy Dependence of the UEQCD@LHC 2012QCD@LHC 2012



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!



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



““Transverse” Charged DensityTransverse” Charged Density

PTmax Direction

“Toward”


“Away”

ChgJet#1 Direction

“Toward”


“Away”

Shows the charged particle density in the “transverse” region for charged particles (pT > 0.5 GeV/c, || < 1) at 7 TeV as defined by PTmax, PT(chgjet#1), 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 = 0.5.

"Transverse" Charged Particle Density: dN/dd

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Charged Particles (||<1.0, PT>0.5 GeV/c)

RDF Preliminarypy Tune DW generator level

PTmax

ChgJet#1

DY(muon-pair)70 < M(pair) < 110 GeV

Muon-Pair Direction

“Toward”


“Away”



Jet Radius DependenceJet Radius Dependence

The charged particle density in the “transverse” region as defined by the leading charged particle jet from PYTHIA Tune Z1. The charged particles are in the region pT > 0.5 GeV/c and || < 2.5. Charged particle jets are constructed using the Anti-KT algorithm with d = 0.2, 0.5, and 1.0 from charged particles in the region pT > 0.5 GeV/c and || < 2.5, however, the leading charged particle jet is required to have |(chgjet#1)| < 1.5.

The UE activity is higherfor large jet radius!


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Chgjet#1 (||<1.5)

7 TeV

RDF PreliminarypyZ1 generator level

d = 0.5

d = 0.2

d = 1.0

Tune Z1

It seems that large jet radius “biases” the UE to be more active!



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!

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

Determines the energy dependence of the MPI!



Old PYTHIA default(more initial-state radiation)New PYTHIA default

(less initial-state radiation)

Parameter Tune B Tune A

MSTP(81) 1 1

MSTP(82) 4 4

PARP(82) 1.9 GeV 2.0 GeV

PARP(83) 0.5 0.5

PARP(84) 0.4 0.4

PARP(85) 1.0 0.9

PARP(86) 1.0 0.95

PARP(89) 1.8 TeV 1.8 TeV

PARP(90) 0.25 0.25

PARP(67) 1.0 4.0

Old PYTHIA default(more initial-state radiation)New PYTHIA default

(less initial-state radiation)

Plot shows the “transverse” charged particle density versus PT(chgjet#1) compared to the QCD hard scattering predictions of two tuned versions of PYTHIA 6.206 (CTEQ5L, Set B (PARP(67)=1) and Set A (PARP(67)=4)).


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1.8 TeV ||<1.0 PT>0.5 GeV

CDF Preliminarydata uncorrectedtheory corrected

CTEQ5L

PYTHIA 6.206 (Set A)PARP(67)=4

PYTHIA 6.206 (Set B)PARP(67)=1

Run 1 Analysis

Run 1 PYTHIA Tune ARun 1 PYTHIA Tune APYTHIA 6.206 CTEQ5L

CDF Default!



““Transverse” Charged DensitiesTransverse” Charged DensitiesEnergy DependenceEnergy Dependence

"Transverse" Charged PTsum Density: dPTsum/dd

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Pythia 6.206 (Set A) 630 GeV ||<1.0 PT>0.4 GeV

CTEQ5L

HERWIG 6.4 = 0.25

= 0

= 0.16

"Min Transverse" PTsum Density: dPTsum/dd

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630 GeV ||<1.0 PT>0.4 GeV

= 0.25HERWIG 6.4

= 0.16 = 0

CTEQ5L

Pythia 6.206 (Set A)

Shows the “transverse” charged PTsum density (||<1, PT>0.4 GeV) versus PT(charged jet#1) at 630 GeV predicted by HERWIG 6.4 (PT(hard) > 3 GeV/c, CTEQ5L) and a tuned version of PYTHIA 6.206 (PT(hard) > 0, CTEQ5L, Set A, = 0, = 0.16 (default) and = 0.25 (preferred)).

Also shown are the PTsum densities (0.16 GeV/c and 0.54 GeV/c) determined from the Tano, Kovacs, Huston, and Bhatti “transverse” cone analysis at 630 GeV.

Hard-Scattering Cut-Off PT0

1

2

3

4

5

100 1,000 10,000 100,000

CM Energy W (GeV)

PT

0

(Ge

V/c

)

PYTHIA 6.206

= 0.16 (default)

= 0.25 (Set A))

Lowering PT0 at 630 GeV (i.e. increasing ) increases UE activity

resulting in less energy dependence.

Increasing produces less energy dependence for the UE resulting in

less UE activity at the LHC!

Reference pointE0 = 1.8 TeV

Rick Field Fermilab MC WorkshopOctober 4, 2002!



Min-Bias “Associated”Min-Bias “Associated”Charged Particle DensityCharged Particle Density

Shows the “associated” charged particle density in the “transverse” region as a function of PTmax for charged particles (pT > 0.5 GeV/c, || < 1, not including PTmax) for “min-bias” events at 0.2 TeV, 0.9 TeV, 1.96 TeV, 7 TeV, 10 TeV, 14 TeV predicted by PYTHIA Tune DW at the particle level (i.e. generator level).

PTmax Direction

“Toward”


“Away”

PTmax Direction

“Toward”


“Away”

RHIC Tevatron

0.2 TeV → 1.96 TeV (UE increase ~2.7 times)

PTmax Direction

“Toward”


“Away”

LHC

1.96 TeV → 14 TeV (UE increase ~1.9 times)

Linear scale!


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Min-Bias 14 TeV

1.96 TeV

0.2 TeV

7 TeV

0.9 TeV

10 TeV


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PTmax = 5.25 GeV/c

RHIC

Tevatron900 GeV

LHC7

LHC14

LHC10



Min-Bias “Associated”Min-Bias “Associated”Charged Particle DensityCharged Particle Density

Shows the “associated” charged particle density in the “transverse” region as a function of PTmax for charged particles (pT > 0.5 GeV/c, || < 1, not including PTmax) for “min-bias” events at 0.2 TeV, 0.9 TeV, 1.96 TeV, 7 TeV, 10 TeV, 14 TeV predicted by PYTHIA Tune DW at the particle level (i.e. generator level).

Log scale!


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Min-Bias 14 TeV

1.96 TeV

0.2 TeV

7 TeV

0.9 TeV

10 TeV


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PTmax = 5.25 GeV/c

RHIC

Tevatron

900 GeV

LHC7

LHC14LHC10

PTmax Direction

“Toward”


“Away”

PTmax Direction

“Toward”


“Away”

LHC7 LHC14

7 TeV → 14 TeV (UE increase ~20%)

Linear on a log plot!



PYTHIA Tune DWPYTHIA Tune DW

PTmax Direction

“Toward”


“Away”


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ATLAS corrected dataTune DW generator level

900 GeV

7 TeV


ATLAS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune DW at the generator level.

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c and || < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation.


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900 GeV

CMS Preliminarydata uncorrected

pyDW + SIM


7 TeV

CMS ATLAS

PT(chgjet#1) Direction

“Toward”


“Away”


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CDF 1.96 TeVLeading Jet

RDF Preliminarydata corrected

pyDW generator level

Charged Particles (PT>0.5 GeV/c, || < 1.0)



PYTHIA Tune DWPYTHIA Tune DW

Ratio of CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c and || < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation.


0.0

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PT(chgjet#1) (GeV/c)

Rat

io:

7 T

eV/9

00 G

eV


pyDW + SIM

Charged Particles (||<2.0, PT>0.5 GeV/c) 7 TeV / 900 GeV

CMS


“Toward”


“Away”

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c and || < 2. The data are uncorrected and compared with PYTHIA Tune DW after detector simulation.


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7 TeV

CMS


“Toward”


“Away”

Ratio



PYTHIA Tune Z1PYTHIA Tune Z1

Proton Proton

PT(hard)

Outgoing Parton

Outgoing Parton




I believe that it is time to move to PYTHIA 6.4 (pT-ordered parton showers and new MPI model)!

Tune Z1: I started with the parameters of ATLAS Tune AMBT1, 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 7 TeV.

UE&MB@CMSUE&MB@CMS

All my previous tunes (A, DW, DWT, D6, D6T, CW, X1, and X2) were PYTHIA 6.4 tunes using the old Q2-ordered parton showers and the old MPI model (really 6.2 tunes)!

PARP(90)

Color

Connections

PARP(82)

Diffraction

The ATLAS Tune AMBT1 was designed to fit the inelastic data for Nchg ≥ 6 and to fit the PTmax UE data with PTmax > 10 GeV/c. Tune AMBT1 is primarily a min-bias tune, while Tune Z1 is a UE tune!



PYTHIA Tune Z1PYTHIA Tune Z1Parameter

Tune Z1

(R. Field CMS)Tune AMBT1

(ATLAS)

Parton Distribution Function CTEQ5L LO*

PARP(82) – MPI Cut-off 1.932 2.292

PARP(89) – Reference energy, E0 1800.0 1800.0

PARP(90) – MPI Energy Extrapolation 0.275 0.25

PARP(77) – CR Suppression 1.016 1.016

PARP(78) – CR Strength 0.538 0.538

PARP(80) – Probability colored parton from BBR 0.1 0.1

PARP(83) – Matter fraction in core 0.356 0.356

PARP(84) – Core of matter overlap 0.651 0.651

PARP(62) – ISR Cut-off 1.025 1.025

PARP(93) – primordial kT-max 10.0 10.0

MSTP(81) – MPI, ISR, FSR, BBR model 21 21

MSTP(82) – Double gaussion matter distribution 4 4

MSTP(91) – Gaussian primordial kT 1 1

MSTP(95) – strategy for color reconnection 6 6

Parameters not shown are the PYTHIA 6.4

defaults!



CMS UE DataCMS UE Data

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c and || < 2.0. The data are corrected and compared with PYTHIA Tune Z1 at the generator level.

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle jet (chgjet#1) for charged particles with pT > 0.5 GeV/c and || < 2.0. The data are corrected and compared with PYTHIA Tune Z1 at the generator level.

CMS


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CMS Preliminarydata corrected

Tune Z1 generator level

900 GeV

7 TeV


"Transverse" Charged PTsum Density: dPT/dd

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CMS Preliminarydata corrected


900 GeV

7 TeV

Tune Z1

Very nice agreement!CMS corrected

data!CMS corrected

data!

CMSTune Z1



ATLAS UE DataATLAS UE Data

ATLAS published data at 900 GeV and 7 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune Z1 at the generrator level.

ATLAS published data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 2.5. The data are corrected and compared with PYTHIA Tune Z1 at the generator level.

ATLASATLAS

Tune Z1Tune Z1

ATLAS publication – arXiv:1012.0791December 3, 2010


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RDF Preliminary ATLAS corrected dataTune Z1 generator level

900 GeV

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RDF PreliminaryATLAS corrected data


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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






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

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

ATLAS (solid blue)ALICE (open black)

RDF Preliminary corrected data


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Charged Particles (|| < 0.8, PT > 0.5 GeV/c) ATLAS (solid blue)ALICE (open black)


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



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New CMS UE DataNew CMS UE Data

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected and compared with PYTHIA Tune Z1 at the generator level.

CMS preliminary data at 900 GeV and 7 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The data are corrected and compared with PYTHIA Tune Z1 at the generator level.

Very nice agreement!CMS corrected

data!CMS corrected

data!


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corrected dataTune Z1 generator level


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CMS Preliminary corrected data



900 GeV

7 TeV

Tune Z1

CMS CMSTune Z1


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Tune Z1


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8 TeV

Less than 4% change!



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

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Charged Particles (|| < 0.8, PT > 0.5 GeV/c) ATLAS (solid blue)ALICE (open black)


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CMS (solid red)ATLAS (solid blue)ALICE (open black)



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corrected data




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PT

su

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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



New CDF UE DataNew CDF UE Data

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0.

PTmax Direction

“Toward”


“Away”


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CDF Preliminary Corrected Data


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Tune Z1 Generator Level


1.96 TeV

300 GeV

900 GeV

PYTHIA Tune Z1

900 GeV37,075,521 Events

300 GeV7,233,840 Events

1.96 TeV25,371,145 Events




New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0.

PTmax Direction

“Toward”


“Away”


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1.96 TeV

300 GeV

900 GeV

PYTHIA Tune Z1






New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged particle average pT, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0.

PTmax Direction

“Toward”


“Away”

"Transverse" Charged Particle AvePT

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PYTHIA Tune Z1





Energy DependenceEnergy Dependence"Transverse" Charged Particle Density: dN/dd

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5.0 < PTmax < 6.0 GeV/c


New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0 for 5.0 < PTmax < 6.0 GeV/c.


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d D

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ity CDF Preliminary

Corrected Data


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300 GeV

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1.96 TeV

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900 GeV

PYTHIA Tune Z1


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5.0 < PTmax < 6.0 GeV/c



PYTHIA Tune Z1



Energy DependenceEnergy Dependence

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0.

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged PTsum density, dPT/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0 for 5.0 < PTmax < 6.0 GeV/c.


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1.96 TeV

300 GeV

900 GeV


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5.0 < PTmax < 6.0 GeV/c



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1.96 TeV

300 GeV

900 GeV

PYTHIA Tune Z1




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Tune Z1

"Transverse" Charged Density

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5.0 < PTmax < 6.0 GeV/c

PTsum

Nchg



Tune Z1



Energy DependenceEnergy Dependence

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged particle average pT as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0.

New Corrected CDF data at 300 GeV, 900 GeV, and 1.96 TeV on the “transverse” charged particle average pT as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0 for 5.0 < PTmax < 6.0 GeV/c.


0.6

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Tune Z1


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PYTHIA Tune Z1





Energy Ratio: 1960/300Energy Ratio: 1960/300


Ratio of the CDF data at 300 GeV and 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0. Shows 1.96 TeV divided by 300 GeV.


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d D

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Corrected Data


1.96 TeV

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900 GeV


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Ra

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CDF Preliminary Corrected Data Ratio


1.96 TeV divided by 300 GeV


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1.96 TeV

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900 GeV

PYTHIA Tune Z1


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PTmax (GeV/c)

Ra

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Tune Z1





Ratio of the CDF data at 300 GeV and 900 GeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0. Shows 900 GeV divided by 300 GeV.


1.0

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PTmax (GeV/c)

Ra

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900 GeV divided by 300 GeV


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PYTHIA Tune Z1


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Tune Z1 Generator LevelTune Z1





Ratio of the CDF data at 900 GeV and 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0. Shows 1.96 TeV divided by 900 GeV.


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PYTHIA Tune Z1


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Tune Z1



PYTHIA 6.4 Tune Z1PYTHIA 6.4 Tune Z1"Transverse" Charged Particle Density: dN/dd

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Corrected DataTune Z1 Generator Level


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PYTHIA Tune Z1


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PYTHIA Tune Z1


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Tune Z1


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Tune Z1 Generator LevelTune Z1


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Tune Z1


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RDF Preliminary Corrected Data

Charged Particles (PT>0.5 GeV/c)

1.96 TeV

300 GeV

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PYTHIA Tune Z1

7 TeV

CDF

CDFCDF

ALICE

ATLAS CMS



PYTHIA 6.4 Tune Z1PYTHIA 6.4 Tune Z1"Transverse" Charged PTsum Density: dPT/dd

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PYTHIA Tune Z1




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Tune Z1


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Tune Z1


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Tune Z1


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Tune Z1


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PYTHIA Tune Z1


Tune Z1 Generator Level 7 TeV

CDF

CDF

CDF

ALICE

ATLASCMS



PYTHIA 6.4 Tune Z1PYTHIA 6.4 Tune Z1"Transverse" Charged Particle AvePT

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Tune Z1


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Tune Z1

"Transverse" Charged Particle Average PT

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Tune Z1

"Transverse" Charged Particle Average PT

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PTmax versus Leading JetPTmax versus Leading Jet"Transverse" Charged Particle Density: dN/dd

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1.96 TeV

CDF PublishedCorrected Data

PYTHIA Tune Z1

Published CDF Run 2 data at 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading calorimeter jet (jet#1) for charged particles with pT > 0.5 GeV/c and || < 1.0 compared with PYTHIA Tune Z1.


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CDF PreliminaryCorrected Data


1.96 TeV

PYTHIA Tune Z1

New CDF data 1.96 TeV on the “transverse” charged particle density, dN/dd, as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 1.0 compared with PYTHIA Tune Z1.

Yikes!???


0.0

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Leading JetPTmax1.96 TeV


PYTHIA Tune Z1


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Leading Jet

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PYTHIA Tune Z1


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Charged Particles (||<1.0, PT>0.5 GeV/c) Leading Jet

PTmax

1.96 TeV


PYTHIA Tune Z1

OkayNo inconsistency

But need to understand!



More Coming Soon!More Coming Soon!CDF - Many More UE Observables: Nchg density, PTsum

density, average pT, “toward”, “away”, “transverse”, “transMAX”, “transMIN”, distributions, etc..

CDF - Two Ranges: Must do (pT > 0.5 GeV/c, || < 0.8) as well as (pT > 0.5 GeV, || < 1).

CDF - Min-Bias: Many MB observables: Multiplicity, dN/d, pT distribution, <pT> versus Nchg, etc.

Soon we will have MB & UE data at300 GeV, 900 GeV, 1.96 TeV, 7 TeV, and 8 TeV!

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

What we are learning shouldallow for a deeper understanding of MPI

which will result in more precisepredictions at the future LHC energy of 13 TeV!

qcd@lhc 2012

Documents

charged particle density

charged particles

particle correlations

particle level

particle jets

transverse region

pythia tune z1

region pt