MPI@LHC08, Perugia, Italy October 27, 2008 Rick Field – Florida/CDF/CMSPage 1 Studying the...

MPI@LHC08, Perugia, Italy October 27, 2008

Rick Field – Florida/CDF/CMS

Studying the Underlying Event Studying the Underlying Event at CDF and the LHCat CDF and the LHC

Rick FieldUniversity of Florida

Outline of Talk

CMS at the LHCCDF Run 2

Perugia, Italy October 27. 2008“Leading Jet” vs Z-Boson

Rick FieldCraig GroupDeepak Kar

The “Towards”, “Away”, and “Transverse” regions of - space.

Four Jet Topologies plus Drell-Yan.

The “transMAX” and “transMIN” regions.

Look at <pT> versus Nchg in “min-bias” and Drell-Yan.

Show some extrapolations of Drell-Yan to the LHC.

The observables: First look at average quantities. Then do distributions.



UE&MB@CMSUE&MB@CMS

Measure Min-Bias and the “Underlying Event” at CMS The plan involves two phases. Phase 1 would be to measure min-bias and the “underlying event”

as soon as possible (when the luminosity is low), perhaps during commissioning. We would then tune the QCD Monte-Carlo models for all the other CMS analyses. Phase 1 would be a service to the rest of the collaboration. As the measurements become more reliable we would re-tune the QCD Monte-Carlo models if necessary and begin Phase 2.

Phase 2 is “physics” and would include comparing the min-bias and “underlying event” measurements at the LHC with the measurements we have done (and are doing now) at CDF and then writing a physics publication.

Initial Group MembersRick Field (Florida)

Darin Acosta (Florida) Paolo Bartalini (Florida)Albert De Roeck (CERN)

Livio Fano' (INFN/Perugia at CERN)Filippo Ambroglini (INFN/Perugia at CERN)

Khristian Kotov (UF Student, Acosta)

UE&MB@CMSUE&MB@CMS

Perugia, Italy, March 2006

University of Perugia

Florida-Perugia-CERN

PTDR Volume 2 Section 3.3.2

See the talks by Filippo Ambroglini

andFlorian Bechtel

tomorrow morning!



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

Initial-State Radiation

Final-State Radiation

Hard Scattering

PT(hard)

Outgoing Parton

Outgoing Parton



Proton AntiProton

Underlying Event Underlying Event

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!



QCD Monte-Carlo Models:QCD Monte-Carlo Models:Lepton-Pair ProductionLepton-Pair Production

Start with the perturbative Drell-Yan muon pair production and add initial-state gluon radiation (in the leading log approximation or modified leading log approximation).

Proton AntiProton


Proton AntiProton


Lepton-Pair Production

Lepton

Anti-Lepton


Lepton-Pair Production

Lepton

Anti-Lepton


“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-state radiation.

“Jet”

Proton AntiProton

High PT Z-Boson Production

Z-boson

Outgoing Parton

Initial-State Radiation Final-State Radiation


Z-boson

Outgoing Parton



“Hard Scattering” Component



-1 +1

2

0

Leading Jet

Toward Region

Transverse Region

Transverse Region

Away Region

Away Region

Jet #1 Direction

“Transverse” “Transverse”

“Toward”

“Away”

“Toward-Side” Jet

“Away-Side” Jet

““Towards”, “Away”, “Transverse”Towards”, “Away”, “Transverse”

Look at correlations in the azimuthal angle relative to the leading charged particle jet (|| < 1) or the leading calorimeter jet (|| < 2).

Define || < 60o as “Toward”, 60o < | < 120o as “Transverse ”, and || > 120o as “Away”. Each of the three regions have area = 2×120o = 4/3.

Jet #1 Direction

“Toward”


“Away”

Correlations relative to the leading jetCharged particles pT > 0.5 GeV/c || < 1Calorimeter towers ET > 0.1 GeV || < 1“Transverse” region is

very sensitive to the “underlying event”!

Look at the charged particle density, the

charged PTsum density and the ETsum density in

all 3 regions!

Z-Boson Direction



Event TopologiesEvent Topologies“Leading Jet” events correspond to the leading

calorimeter jet (MidPoint R = 0.7) in the region || < 2 with no other conditions.

Jet #1 Direction

“Toward”


“Away”

“Leading Jet”

“Leading ChgJet” events correspond to the leading charged particle jet (R = 0.7) in the region || < 1 with no other conditions.

ChgJet #1 Direction

“Toward”


“Away”

Jet #1 Direction

“Toward”


“Away”

Jet #2 Direction

“Charged Jet”

“Inc2J Back-to-Back”

“Exc2J Back-to-Back”

“Inclusive 2-Jet Back-to-Back” events are selected to have at least two jets with Jet#1 and Jet#2 nearly “back-to-back” (12 > 150o) with almost equal transverse energies (PT(jet#2)/PT(jet#1) > 0.8) with no other conditions .

“Exclusive 2-Jet Back-to-Back” events are selected to have at least two jets with Jet#1 and Jet#2 nearly “back-to-back” (12 > 150o) with almost equal transverse energies (PT(jet#2)/PT(jet#1) > 0.8) and PT(jet#3) < 15 GeV/c.

subset

subset

Z-Boson Direction

“Toward”


“Away”

Z-Boson“Z-Boson” events are Drell-Yan events with 70 < M(lepton-pair) < 110 GeV with no other conditions.



““transMAX” & “transMIN”transMAX” & “transMIN”

Define the MAX and MIN “transverse” regions (“transMAX” and “transMIN”) on an event-by-event basis with MAX (MIN) having the largest (smallest) density. Each of the two “transverse” regions have an area in - space of 4/6.

The “transMIN” region is very sensitive to the “beam-beam remnant” and the soft multiple parton interaction components of the “underlying event”.

Jet #1 Direction

“Toward”

“TransMAX” “TransMIN”

“Away”

Jet #1 Direction


“Toward”

“Away”

“Toward-Side” Jet

“Away-Side” Jet

Jet #3

The difference, “transDIF” (“transMAX” minus “transMIN”), is very sensitive to the “hard scattering” component of the “underlying event” (i.e. hard initial and final-state radiation).

Area = 4/6

“transMIN” very sensitive to the “beam-beam remnants”!

The overall “transverse” density is the average of the “transMAX” and “transMIN” densities.

Z-Boson Direction



Jet #1 Direction

“Toward”


“Away”

Jet #1 Direction

“Toward”


“Away”

Jet #2 Direction

“Back-to-Back”

Observable Particle Level Detector Level

dNchg/ddNumber of charged particles

per unit -(pT > 0.5 GeV/c, || < 1)

Number of “good” charged tracksper unit -

(pT > 0.5 GeV/c, || < 1)

dPTsum/ddScalar pT sum of charged particles

per unit -(pT > 0.5 GeV/c, || < 1)

Scalar pT sum of “good” charged tracks per

unit -(pT > 0.5 GeV/c, || < 1)

<pT>Average pT of charged particles

(pT > 0.5 GeV/c, || < 1)

Average pT of “good” charged tracks

(pT > 0.5 GeV/c, || < 1)

PTmax

Maximum pT charged particle

(pT > 0.5 GeV/c, || < 1)

Require Nchg ≥ 1

Maximum pT “good” charged tracks

(pT > 0.5 GeV/c, || < 1)

Require Nchg ≥ 1

dETsum/ddScalar ET sum of all particles

per unit -(all pT, || < 1)

Scalar ET sum of all calorimeter towers

per unit -(ET > 0.1 GeV, || < 1)

PTsum/ETsum

Scalar pT sum of charged particles

(pT > 0.5 GeV/c, || < 1)

divided by the scalar ET sum of

all particles (all pT, || < 1)

Scalar pT sum of “good” charged tracks

(pT > 0.5 GeV/c, || < 1)

divided by the scalar ET sum of

calorimeter towers (ET > 0.1 GeV, || < 1)

“Leading Jet”

Observables at theObservables at theParticle and Detector LevelParticle and Detector Level



CDF Run 1 PCDF Run 1 PTT(Z)(Z)

Shows the Run 1 Z-boson pT distribution (<pT(Z)> ≈ 11.5 GeV/c) compared with PYTHIA Tune A (<pT(Z)> = 9.7 GeV/c), and PYTHIA Tune AW (<pT(Z)> = 11.7 GeV/c).

Parameter Tune A Tune AW

MSTP(81) 1 1

MSTP(82) 4 4

PARP(82) 2.0 GeV 2.0 GeV

PARP(83) 0.5 0.5

PARP(84) 0.4 0.4

PARP(85) 0.9 0.9

PARP(86) 0.95 0.95

PARP(89) 1.8 TeV 1.8 TeV

PARP(90) 0.25 0.25

PARP(62) 1.0 1.25

PARP(64) 1.0 0.2

PARP(67) 4.0 4.0

MSTP(91) 1 1

PARP(91) 1.0 2.1

PARP(93) 5.0 15.0

The Q2 = kT2 in s for space-like showers is scaled by PARP(64)!

Effective Q cut-off, below which space-like showers are not evolved.

UE Parameters

ISR Parameters

Intrensic KT

PYTHIA 6.2 CTEQ5LZ-Boson Transverse Momentum

0.00

0.04

0.08

0.12

0 2 4 6 8 10 12 14 16 18 20

Z-Boson PT (GeV/c)

PT

Dis

trib

uti

on

1/N

dN

/dP

T

CDF Run 1 Data

PYTHIA Tune A

PYTHIA Tune AW

CDF Run 1published

1.8 TeV

Normalized to 1

Tune used by the CDF-EWK group!



JetJet--Jet Correlations (DJet Correlations (DØ)Ø)

Jet#1-Jet#2 Distribution Jet#1-Jet#2

MidPoint Cone Algorithm (R = 0.7, fmerge = 0.5)

L = 150 pb-1 (Phys. Rev. Lett. 94 221801 (2005))Data/NLO agreement good. Data/HERWIG agreement

good.Data/PYTHIA agreement good provided PARP(67) =

1.0→4.0 (i.e. like Tune A, best fit 2.5).



CDF Run 1 PCDF Run 1 PTT(Z)(Z)

Shows the Run 1 Z-boson pT distribution (<pT(Z)> ≈ 11.5 GeV/c) compared with PYTHIA Tune DW, and HERWIG.

Parameter Tune DW Tune AW

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(62) 1.25 1.25

PARP(64) 0.2 0.2

PARP(67) 2.5 4.0

MSTP(91) 1 1

PARP(91) 2.1 2.1

PARP(93) 15.0 15.0

UE Parameters

ISR Parameters

Intrensic KT

PYTHIA 6.2 CTEQ5L Z-Boson Transverse Momentum

0.00

0.04

0.08

0.12

0 2 4 6 8 10 12 14 16 18 20

Z-Boson PT (GeV/c)

PT

Dis

trib

uti

on

1/N

dN

/dP

T

CDF Run 1 Data

PYTHIA Tune DW

HERWIG

CDF Run 1published

1.8 TeV

Normalized to 1

Tune DW has a lower value of PARP(67) and slightly more MPI!

Tune DW uses D0’s perfered value of PARP(67)!



PYTHIA 6.2 TunesPYTHIA 6.2 TunesParameter Tune AW Tune DW Tune D6

PDF CTEQ5L CTEQ5L CTEQ6L

MSTP(81) 1 1 1

MSTP(82) 4 4 4

PARP(82) 2.0 GeV 1.9 GeV 1.8 GeV

PARP(83) 0.5 0.5 0.5

PARP(84) 0.4 0.4 0.4

PARP(85) 0.9 1.0 1.0

PARP(86) 0.95 1.0 1.0

PARP(89) 1.8 TeV 1.8 TeV 1.8 TeV

PARP(90) 0.25 0.25 0.25

PARP(62) 1.25 1.25 1.25

PARP(64) 0.2 0.2 0.2

PARP(67) 4.0 2.5 2.5

MSTP(91) 1 1 1

PARP(91) 2.1 2.1 2.1

PARP(93) 15.0 15.0 15.0

Intrinsic KT

ISR Parameter

UE Parameters

Uses CTEQ6L

All use LO s with = 192 MeV!

Tune A energy dependence!



PYTHIA 6.2 TunesPYTHIA 6.2 TunesParameter Tune DWT Tune D6T ATLAS

PDF CTEQ5L CTEQ6L CTEQ5L

MSTP(81) 1 1 1

MSTP(82) 4 4 4

PARP(82) 1.9409 GeV 1.8387 GeV 1.8 GeV

PARP(83) 0.5 0.5 0.5

PARP(84) 0.4 0.4 0.5

PARP(85) 1.0 1.0 0.33

PARP(86) 1.0 1.0 0.66

PARP(89) 1.96 TeV 1.96 TeV 1.0 TeV

PARP(90) 0.16 0.16 0.16

PARP(62) 1.25 1.25 1.0

PARP(64) 0.2 0.2 1.0

PARP(67) 2.5 2.5 1.0

MSTP(91) 1 1 1

PARP(91) 2.1 2.1 1.0

PARP(93) 15.0 15.0 5.0

Intrinsic KT

ISR Parameter

UE Parameters

All use LO s with = 192 MeV!

ATLAS energy dependence!These are “old” PYTHIA 6.2 tunes!

See the talks byArthur Moraes

andHendrik Hoeth

for “new” tunes!



JIMMY at CDFJIMMY at CDFThe Energy in the “Underlying

Event” in High PT Jet Production

“Transverse” <Densities> vs PT(jet#1)

Jet #1 Direction

“Toward”


“Away”

"Transverse" PTsum Density: dPT/dd

0.0

0.4

0.8

1.2

1.6

0 50 100 150 200 250 300 350 400 450 500

PT(particle jet#1) (GeV/c)

"Tra

nsv

erse

" P

Tsu

m D

ensi

ty (

GeV

/c)

PY Tune A

HW

1.96 TeV

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

CDF Run 2 Preliminarygenerator level theory

MidPoint R = 0.7 |(jet)| < 2

"Leading Jet"

JIMMY Default

JM325

"Transverse" ETsum Density: dET/dd

0.0

1.0

2.0

3.0

4.0

0 100 200 300 400 500

PT(particle jet#1) (GeV/c)

"Tra

ns

vers

e" E

Tsu

m D

ensi

ty (

GeV

) 1.96 TeV

All Particles (||<1.0)

HW

PY Tune A

MidPoint R = 0.7 |(jet)| < 2CDF Run 2 Preliminarygenerator level theory

"Leading Jet"

JIMMY Default

JM325

JIMMY: MPIJ. M. Butterworth

J. R. ForshawM. H. Seymour

JIMMY was tuned to fit the energy density in the “transverse” region for

“leading jet” events!JIMMY

Runs with HERWIG and adds multiple parton interactions!

PT(JIM)= 2.5 GeV/c.

PT(JIM)= 3.25 GeV/c.

Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




The Drell-Yan JIMMY TunePTJIM = 3.6 GeV/c,

JMRAD(73) = 1.8JMRAD(91) = 1.8



Z-Boson Direction

“Toward”


“Away”

Charged Particle DensityCharged Particle Density

Data at 1.96 TeV on the density of charged particles, dN/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).

Jet #1 Direction

“Toward”


“Away”

Charged Particle Density: dN/dd

0

1

2

3

4

0 20 40 60 80 100 120 140 160 180 200

PT(jet#1) (GeV/c)

Ave

rag

e C

har

ge

d D

en

sity

CDF Run 2 Preliminarydata corrected

pyA generator level

"Leading Jet"MidPoint R=0.7 |(jet#1)|<2


"Away"

"Toward"

"Transverse"


0

1

2

3

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ave

rag

e C

har

ge

d D

ensi

ty


pyAW generator level"Away"

"Transverse"

"Toward"

"Drell-Yan Production"70 < M(pair) < 110 GeV

Charged Particles (||<1.0, PT>0.5 GeV/c)excluding the lepton-pair

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




"Transverse" Charged Particle Density: dN/dd

0.0

0.3

0.6

0.9

1.2

0 20 40 60 80 100 120 140 160 180 200

PT(jet#1) or PT(Z-Boson) (GeV/c)

"Tra

nsv

erse

" C

ha

rged

Den

sit

y


generator level theory


"Leading Jet"

"Z-Boson"

"Away" Charged Particle Density: dN/dd

0

1

2

3

4

0 20 40 60 80 100 120 140 160 180 200


"Aw

ay"

Ch

arg

ed D

ensi

ty




"Leading Jet"

"Z-Boson"

"Away" Charged Particle Density: dN/dd

0

1

2

3

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Aw

ay"

Ch

arg

ed D

en

sity





JIM

HW

pyAW

HERWIG + JIMMYTune (PTJIM = 3.6)



Z-Boson Direction

“Toward”


“Away”

Charged PTsum DensityCharged PTsum Density

Data at 1.96 TeV on the charged scalar PTsum density, dPT/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” and “Leading Jet” events as a function of the leading jet pT or PT(Z) for the “toward”, “away”, and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).

Jet #1 Direction

“Toward”


“Away”

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




Charged PTsum Density: dPT/dd

0.1

1.0

10.0

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ch

arg

ed

P

Ts

um

Den

sity

(G

eV

/c)


pyAW generator level


"Away"

"Transverse"

"Toward"



0.1

1.0

10.0

100.0

0 20 40 60 80 100 120 140 160 180 200

PT(jet#1) (GeV/c)

Ch

arg

ed

P

Tsu

m D

en

sity

(G

eV

/c)


pyA generator level



"Toward"

"Away"

"Transverse"

"Transverse" Charged PTsum Density: dPT/dd

0.0

0.5

1.0

1.5

2.0

0 20 40 60 80 100 120 140 160 180 200


"Tra

nsv

erse

" P

Ts

um

Den

sity

(G

eV/c

)




"Leading Jet"

"Z-Boson"

"Away" Charged PTsum Density: dPT/dd

0

5

10

15

20

0 20 40 60 80 100 120 140 160 180 200


"Aw

ay"

PT

sum

Den

sit

y (G

eV

/c) CDF Run 2 Preliminary

data correctedgenerator level theory


"Leading Jet"

"Z-Boson"

"Away" Charged PTsum Density: dPT/dd

0

4

8

12

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Aw

ay"

PT

sum

Den

sit

y (G

eV





pyAW

HW

JIM



The “TransMAX/MIN” RegionsThe “TransMAX/MIN” Regions

Data at 1.96 TeV on the charged particle density, dN/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” and “Leading Jet” events as a function of PT(Z) or the leading jet pT for the “transMAX”, and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




"TransMAX/MIN" Charged Particle Density: dN/dd

0.0

0.4

0.8

1.2

1.6

0 50 100 150 200 250 300 350 400

PT(jet#1) (GeV/c)

"Tra

ns

vers

e"

Ch

arg

ed D

ensi

ty CDF Run 2 Preliminarydata corrected




PY Tune A

HW

"transMAX"

"transMIN"


0.0

0.4

0.8

1.2

1.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Tra

ns

vers

e"

Ch

arg

ed D

ensi

ty





"transMAX"

"transMIN"

pyAW

HW


0.0

0.4

0.8

1.2

1.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Tra

ns

vers

e"

Ch

arg

ed D

ensi

ty





"transMAX"

"transMIN"

pyDW

JIM

ATLAS

"TransDIF" Charged Particle Density: dN/dd

0.0

0.3

0.6

0.9

1.2

0 50 100 150 200 250 300 350 400

PT(jet#1) (GeV/c)

Tra

nsM

AX

- T

ran

sMIN

Den

sity





HW

PY Tune A


0.0

0.3

0.6

0.9

1.2

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Tra

nsM

AX

- T

ran

sMIN

Den

sity





pyAW

HW


0.0

0.3

0.6

0.9

1.2

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Tra

nsM

AX

- T

ran

sMIN

Den

sity





pyDW

JIM

ATLAS


0.0

0.3

0.6

0.9

1.2

0 20 40 60 80 100 120 140 160 180 200


"Tra

ns

DIF

" C

har

ged

De

ns

ity




"Z-Boson"

"Leading Jet"

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

Jet #1 Direction

“Toward”


“Away”

Z-Boson Direction

“Toward”


“Away”



The “TransMAX/MIN” RegionsThe “TransMAX/MIN” Regions

Data at 1.96 TeV on the charged scalar PTsum density, dPT/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” and “Leading Jet” events as a function of PT(Z) or the leading jet pT for the “transMAX”, and “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and Tune A, respectively, at the particle level (i.e. generator level).

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




Data at 1.96 TeV on the charged scalar PTsum density, dPT/dd, with pT > 0.5 GeV/c and || < 1 for “leading jet” events as a function of the leading jet pT and for Z-Boson events as a function of PT(Z) for “TransDIF” = “transMAX” minus “transMIN” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune A and HERWIG (without MPI) at the particle level (i.e. generator level).

Jet #1 Direction

“Toward”


“Away”

Z-Boson Direction

“Toward”


“Away”

"TransMAX/MIN" Charged PTsum Density

0.0

1.0

2.0

3.0

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Tra

nsv

erse

" P

Ts

um

Den

sity

(G

eV/c

)





"transMAX"

"transMIN"

pyAW

HW

"TransMAX/MIN" Charged PTsum Density

0.0

1.0

2.0

3.0

0 50 100 150 200 250 300 350 400

PT(jet#1) (GeV/c)

"Tra

nsv

erse

" P

Ts

um

Den

sity

(G

eV/c

)





PY Tune A

HW

"transMAX"

"transMIN"

"TransDIF" Charged PTsum Density: dPT/dd

0.0

1.0

2.0

3.0

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Tra

ns

MA

X -

Tra

nsM

IN D

ens

ity

(Ge

V/c

)





pyAW

HW


0.0

1.0

2.0

3.0

0 50 100 150 200 250 300 350 400

PT(jet#1) (GeV/c)

Tra

ns

MA

X -

Tra

nsM

IN D

ens

ity

(Ge

V/c

)





PY Tune A

HW


0.0

1.0

2.0

3.0

0 20 40 60 80 100 120 140 160 180 200


"Tra

nsD

IF"

PT

sum

Den

sity

(G

eV




"Leading Jet"

"Z-Boson"



Charged Particle <pCharged Particle <pTT>>

Jet #1 Direction

“Toward”


“Away”

Z-BosonDirection

“Toward”


“Away”

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

"Transverse" Average PT

0.5

1.0

1.5

2.0

0 50 100 150 200 250 300 350 400

PT(jet#1) (GeV/c)

"Tra

nsv

erse

" A

vera

ge

PT

(G

eV/c

) CDF Run 2 Preliminarydata corrected




PY Tune A

HW

"Toward" Average PT Charged

0.4

0.8

1.2

1.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

<P

T>

(G

eV/c

)





HWJIM

ATLAS

pyAWpyDW



Z-Boson: “Towards”, Transverse”, Z-Boson: “Towards”, Transverse”, & “TransMIN” Charge Density& “TransMIN” Charge Density

Data at 1.96 TeV on the density of charged particles, dN/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).

Z-BosonDirection

“Toward”


“Away”


0.0

0.3

0.6

0.9

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ch

arg

ed

De

ns

ity


pyAW generator level"Transverse

"Toward"

"Drell-Yan Production"70 < M(pair) < 110 GeV Charged Particles (||<1.0, PT>0.5 GeV/c)

excluding the lepton-pair

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton


Z-boson

Outgoing Parton



0.0

0.3

0.6

0.9

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ch

arg

ed

De

ns

ity





"Toward"

"transMIN"

Z-Boson Direction

“Toward”


“Away”

"Toward" Charged Particle Density: dN/dd

0.0

0.3

0.6

0.9

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

Ch

arg

ed D

ensi

ty





HW

JIM

pyAW

ATLASpyDW

"TransMIN" Charged Particle Density: dN/dd

0.0

0.2

0.4

0.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Tra

ns

MIN

" C

har

ged

De

ns

ity CDF Run 2 Preliminary

data corrected generator level theory



ATLAS

HWpyAW

JIM

pyDW

"TransMIN" Charged Particle Density: dN/dd

0.0

0.2

0.4

0.6

0.8

0 20 40 60 80 100 120 140 160 180 200


"Tra

nsM

IN"

Ch

arg

ed D

en

sit

y CDF Run 2 Preliminarydata corrected



"Leading Jet"

"Z-Boson"



Z-Boson: “Towards”, Transverse”, Z-Boson: “Towards”, Transverse”, & “TransMIN” Charge Density& “TransMIN” Charge Density

Data at 1.96 TeV on the charged scalar PTsum density, dPT/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” and “transverse” regions. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).

Z-BosonDirection

“Toward”


“Away”

Proton AntiProton


Z-boson

Outgoing Parton


Proton AntiProton


Z-boson

Outgoing Parton


Z-Boson Direction

“Toward”


“Away”


0.0

0.6

1.2

1.8

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ch

arg

ed

PT

su

m D

en

sit

y (

GeV

/c)





"Transverse

"Toward"


0.0

0.4

0.8

1.2

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

Ch

arg

ed

PT

su

m D

en

sit

y (

GeV

/c)





"transMIN"

"Toward"

"Toward" Charged PTsum Density: dPT/dd

0.0

0.4

0.8

1.2

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

PT

sum

Den

sity

(G

eV/c

)




Charged Particles (||<1.0, PT>0.5 GeV/c)excluding the lepton-pair HW

JIM

ATLAS

pyAW

pyDW

"TransMIN" Charged PTsum Density: dPT/dd

0.0

0.2

0.4

0.6

0.8

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"Tra

nsM

IN"

PT

sum

Den

sity

(G

eV




Charged Particles (||<1.0, PT>0.5 GeV/c)excluding the lepton-pair HW

ATLAS

pyAW

JIM

pyDW

"TransMIN" Charged PTsum Density: dPT/dd

0.0

0.2

0.4

0.6

0.8

0 20 40 60 80 100 120 140 160 180 200


"Tra

nsM

IN"

PT

sum

Den

sity

(G

eV




"Leading Jet"

"Z-Boson"



Z-Boson: “Towards” RegionZ-Boson: “Towards” Region

Data at 1.96 TeV on the density of charged particles, dN/dd, with pT > 0.5 GeV/c and || < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).

Z-BosonDirection

“Toward”


“Away”

Z-BosonDirection

“Toward”


“Away”


0.0

0.3

0.6

0.9

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

Ch

arg

ed D

ensi

ty





HW

JIM

pyAW

ATLASpyDW


0.0

0.5

1.0

1.5

2.0

0 25 50 75 100 125 150

PT(Z-Boson) (GeV/c)

"To

war

d"

Ch

arg

ed D

ensi

ty


pyDWT generator level



TevatronLHC10

LHC14


0.0

0.5

1.0

1.5

2.0

0 25 50 75 100 125 150

PT(Z-Boson) (GeV/c)

"To

war

d"

Ch

arg

ed D

ensi

ty




HW LHC14

pyDWT LHC14

pyDWT TevatronHW Tevatron


0.0

0.3

0.6

0.9

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

Ch

arg

ed D

ensi

ty


HW generator level



Tevatron

LHC10

LHC14

HW without MPI

DWT



Z-Boson: “Towards” RegionZ-Boson: “Towards” Region

Data at 1.96 TeV on the average pT of charged particles with pT > 0.5 GeV/c and || < 1 for “Z-Boson” events as a function of PT(Z) for the “toward” region. The data are corrected to the particle level (with errors that include both the statistical error and the systematic uncertainty) and are compared with PYTHIA Tune AW and HERWIG (without MPI) at the particle level (i.e. generator level).

Z-BosonDirection

“Toward”


“Away”

Z-BosonDirection

“Toward”


“Away”


0.4

0.8

1.2

1.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

<P

T>

(G

eV/c

)


pyDWT LHC14


pyDWT TevatronHW Tevatron HW LHC14



DWT

HW (without MPI)almost no change!


0.4

0.8

1.2

1.6

0 20 40 60 80 100

PT(Z-Boson) (GeV/c)

"To

war

d"

<P

T>

(G

eV/c

)





HWJIM

ATLAS

pyAWpyDW



Shows the average transverse momentum of charged particles (||<1, pT>0.5 GeV) versus the number of charged particles, Nchg, at the detector level for the CDF Run 2 Min-Bias events.

The charged <PT> rises with Nchg!

Average PT versus Nchg

0.6

0.8

1.0

1.2

1.4

1.6

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Number of Charged Particles

Av

era

ge

PT

(G

eV

/c)

CDF Preliminarydata uncorrectedtheory + CDFSIM

PYTHIA Tune A 1.96 TeV


Min-Bias

Charged <PCharged <PTT> versus N> versus Nchgchg

See the talk by Peter Skands

on Thursday morning!



Min-Bias CorrelationsMin-Bias Correlations

Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT > 0.4 GeV/c, || < 1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle level and are compared with PYTHIA Tune A at the particle level (i.e. generator level).

Proton AntiProton

“Minumum Bias” Collisions


0.6

0.8

1.0

1.2

1.4

0 10 20 30 40 50


Ave

rag

e P

T (

GeV

/c)




Min-Bias1.96 TeV

ATLAS

pyA

pyDW

See the talk by Niccolo Moggithis afternoon!



Average PT versus NchgAverage PT versus Nchg

Proton AntiProton

“Minumum Bias” Collisions


0.6

0.8

1.0

1.2

1.4

0 10 20 30 40 50


Ave

rag

e P

T (

GeV

/c)




Min-Bias1.96 TeV

ATLAS

pyA

pyDW

Proton AntiProton

Drell-Yan Production

Anti-Lepton

Lepton


Data at 1.96 TeV on the average pT of charged particles versus the number of charged particles (pT > 0.4 GeV/c, || < 1) for “min-bias” collisions at CDF Run 2. The data are corrected to the particle leveland are compared with PYTHIA Tune A, Tune DW, and the ATLAS tune at the particle level (i.e. generator level).

Particle level predictions for the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, || < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2.


0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)




HW

JIM

pyAW

ATLAS


0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)





HW

JIM

pyAW

ATLAS



Average PT(Z) versus NchgAverage PT(Z) versus Nchg

Proton AntiProton


Anti-Lepton

Lepton


Data on the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, || < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level ( i.e. generator level).


0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)





HW

JIM

pyAW

ATLAS

PT(Z-Boson) versus Nchg

0

20

40

60

80

0 5 10 15 20 25 30 35 40


Ave

rag

e P

T(Z

) (G

eV

/c)




pyAW

HW

JIM

ATLAS

No MPI!

Predictions for the average PT(Z-Boson) versus the number of charged particles (pT > 0.5 GeV/c, || < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV) at CDF Run 2.

PT(Z-Boson) versus Nchg

0

20

40

60

80

0 5 10 15 20 25 30 35 40


Ave

rag

e P

T(Z

) (G

eV/c

)





pyAW

HW

JIM

ATLAS

Proton AntiProton


Z-boson

Outgoing Parton




Average PT versus NchgAverage PT versus Nchg

Proton AntiProton


Anti-Lepton

Lepton


Predictions for the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, || < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV, PT(pair) < 10 GeV/c) at CDF Run 2.

Average Charged PT versus Nchg

0.6

0.8

1.0

1.2

1.4

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)



PT(Z) < 10 GeV/c


HW

pyAW


0.6

0.8

1.0

1.2

1.4

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)



PT(Z) < 10 GeV/c


HW

JIM

ATLAS

pyAW


0.6

0.8

1.0

1.2

1.4

0 5 10 15 20 25 30 35


Ave

rag

e P

T (

GeV

/c)




PT(Z) < 10 GeV/c


HW

JIM

ATLAS

pyAW

Data the average pT of charged particles versus the number of charged particles (pT > 0.5 GeV/c, || < 1, excluding the lepton-pair) for for Drell-Yan production (70 < M(pair) < 110 GeV, PT(pair) < 10 GeV/c) at CDF Run 2. The data are corrected to the particle level and are compared with various Monte-Carlo tunes at the particle level (i.e. generator level).

PT(Z) < 10 GeV/c

No MPI!


0.6

0.8

1.0

1.2

1.4

0 10 20 30 40


Ave

rag

e P

T (

Ge

V/c

)



Charged Particles (||<1.0)pyA

Min-Bias PT > 0.4 GeV/c

Drell-Yan PT > 0.5 GeV PT(Z) < 10 GeV/c

pyAW

Proton AntiProton

“Minumum Bias” Collisions Remarkably similar behavior! Perhaps indicating that MPI playing an important role in

both processes.



SummarySummary It is important to produce a lot of plots (corrected to the particle level) so that the theorists

can tune and improve the QCD Monte-Carlo models. If they improve the “transverse” region they might miss-up the “toward” region etc.. We need to show the whole story!

There are over 128 plots to get “blessed” and then to published. So far we have only looked at average quantities. We plan to also produce distributions and flow plots.

We are making good progress in understanding and modeling the “underlying event” in jet production and in Drell-Yan. Tune A and Tune AW describe the data very well, although not perfect. However, we do not yet have a perfect fit to all the features of the CDF “underlying event” data!

Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton




I plan to construct a “CDF-QCD Data for Theory” WEBsite with the “blessed” plots together with tables of the data points and errors so that people can have access to the results .

CDF-QCD Data for Theory

Looking at <pT> versus Nchg in Drell-Yan with 70 < Mpair) < 110 GeV and PT(pair) < 5 GeV is a good way to look at MPI and the color connections. The data show the correlations expected from MPI!

Proton AntiProton


Anti-Lepton

Lepton


CDF Run 2 publication. Should be out by the end of the year!

MPI@LHC08, Perugia, Italy October 27, 2008 Rick Field – Florida/CDF/CMSPage 1 Studying the...

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Transcript of MPI@LHC08, Perugia, Italy October 27, 2008 Rick Field – Florida/CDF/CMSPage 1 Studying the...