Rick Field November 11, 2003 A Closer Look at the ...rfield/cdf/CDF_topmass_11-11-03.pdf · Rick Field November 11, 2003 CDF Top Mass Workshop Page 2 of 46 The ﬁTransverseﬂ Region

Rick Field November 11, 2003

CDF Top Mass Workshop Page 1 of 46

A Closer Look at the �Underlying Event� in Run 2: PYTHIA Tune A vs HERWIG

Outline of the Talk

• Look at charged particles (pT > 0.5 GeV/c, |ηηηη| < 1) and study the charged particle and PTsum densities in the MAX and MIN �transverse� regions as defined by the leading calorimeter jet (JetClu, R = 0.7, |ηηηη| < 2) for both �leading jet� and �back-to-back� events. Compare with PYTHIA Tune A + CDFSIM with HERWIG + CDFSIM.

• Use the highest pT particle in the �transverse� region to define �associated� densities and look at �jets structure� in the �underlying event� (i.e. the �transverse� region). Do the particles in the �underlying event� come from �jets�?

• Compare the �birth� of jet#3 in the �transverse� region with the �birth� of jet#1 in �min-bias� collisions.

�Wish list� from the CERN MC Workshop!



The �Transverse� Region

• Look at the �transverse� region as defined by the leading calorimeter jet (JetClu R = 0.7, |ηηηη| < 2).

• Study the charged particles (pT > 0.5 GeV/c, |ηηηη| < 1) and form the charged particle density, dNchg/dηηηηdφφφφ, and the charged scalar pT sum density, dPTsum/dηηηηdφφφφ. Each region �toward�, �away�, and �transverse� region has an area in ηηηη-φφφφ space of 4ππππ/3.

-1 +1

φφφφ

2ππππ

0 ηηηη

Leading Jet

Toward Region

Transverse Region

Transverse Region

Away Region

Away Region

Look at the density of charged particles in the

�transverse� region. Charged Particles

(pT > 0.5 GeV/c, |ηηηη| < 1)

Use the leading jet to define the �transverse� region.

Jet #1 Direction ∆φ∆φ∆φ∆φ

�Toward�

�Transverse� �Transverse�

�Away�



�Transverse� Region: �Leading Jet� vs �Back-to-Back�

• Look at the �transverse� regions as defined by the leading jet (JetClu R

= 0.7, |ηηηη| < 2) or by the leading two jets (JetClu R = 0.7, |ηηηη| < 2). • �Back-to-Back� events are selected to have at least two jets with Jet#1

and Jet#2 nearly �back-to-back� (∆φ∆φ∆φ∆φ12121212 > 150o) with almost equal transverse energies (ET(jet#2)/ET(jet#1) > 0.8).


�Toward�


�Away�

Refer to this as a �Back-to-Back� event


�Toward�


�Away�

Jet #2 Direction

Refer to this as a �Leading Jet� event



Charge Density: �Leading Jet� vs �Back-to-Back�

Charged Particle Density: dN/dηηηηdφφφφ

0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360

∆φ∆φ∆φ∆φ (degrees)

Cha

rged

Par

ticle

Den

sity

Back-to-BackLeading JetMin-Bias

CDF Preliminarydata uncorrected

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

30 < ET(jet#1) < 70 GeV

"Transverse" Region

Jet#1

• Shows the ∆φ∆φ∆φ∆φ dependence of the charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

• Also shows charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 for �min-bias� collisions.


�Toward�


�Away�


�Toward�


�Away�

Jet #2 Direction Log Scale





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

Back-to-BackLeading JetMin-Bias



30 < ET(jet#1) < 70 GeV

"Transverse" Region

Jet#1

• Shows the ∆φ∆φ∆φ∆φ dependence of the charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

• Also shows charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 for �min-bias� collisions.


�Toward�


�Away�


�Toward�


�Away�




Charged PTsum Density: �Leading Jet� vs �Back-to-Back�

Charged PTsum Density: dPT/dηηηηdφφφφ

0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Back-to-BackLeading JetMin-Bias

30 < ET(jet#1) < 70 GeV



Jet#1

"Transverse" Region

• Shows the ∆φ ∆φ ∆φ ∆φ dependence of the charged PTsum density, dPT/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

• Also shows charged PTsum density, dPT/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 for �min-bias� collisions.


�Toward�


�Away�


�Toward�


�Away�




Charged PTsum Density: �Leading Jet� vs �Back-to-Back�


0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Back-to-BackLeading JetMin-Bias

30 < ET(jet#1) < 70 GeV



Jet#1

"Transverse" Region

• Shows the ∆φ ∆φ ∆φ ∆φ dependence of the charged PTsum density, dPT/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

• Also shows charged PTsum density, dPT/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 for �min-bias� collisions.


�Toward�


�Away�


�Toward�


�Away�





Charged Particle Density: dN/dηηηηdφφφφ272

276 280 284 288292

296300

304308

312

316

320

324

328

332

336

340

344

348

352

356

360

4

8

12

16

20

24

28

32

36

40

44

48

5256

6064

6872

7680848892

96100104108112

116120

124128

132

136

140

144

148

152

156

160

164

168

172

176

180

184

188

192

196

200

204

208

212

216

220

224

228

232236

240244

248252

256 260 264 268


30 < ET(jet#1) < 70 GeV


"Transverse" Region

"Transverse" Region

Jet#1

Back-to-BackLeading Jet

• Shows the ∆φ∆φ∆φ∆φ dependence of the charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

Jet #1 Direction

∆φ∆φ∆φ∆φ

�Toward�


�Away�

Jet #2 Direction


�Toward�


�Away�





276 280 284 288292

296300

304308

312

316

320

324

328

332

336

340

344

348

352

356

360

4

8

12

16

20

24

28

32

36

40

44

48

5256

6064

6872

7680848892

96100104108112

116120

124128

132

136

140

144

148

152

156

160

164

168

172

176

180

184

188

192

196

200

204

208

212

216

220

224

228

232236

240244

248252

256 260 264 268


30 < ET(jet#1) < 70 GeV


"Transverse" Region

"Transverse" Region

Jet#1

Back-to-BackLeading Jet

• Shows the ∆φ∆φ∆φ∆φ dependence of the charged particle density, dN/dηηηηdφφφφ, for charged particles in the range pT > 0.5 GeV/c and |ηηηη| < 1 relative to jet#1 for 30 < ET(jet#1) < 70 GeV for �leading jet� and �back-to-back� events.

Jet #1 Direction


�Toward�


�Away�

Jet #2 Direction


�Toward�


�Away�



�Leading Jet� Charge Density: PY Tune A vs HERWIG


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

Leading JetPY Tune A

CDF Preliminarydata uncorrectedtheory + CDFSIM


30 < ET(jet#1) < 70 GeV

"Transverse" Region Jet#1


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

Leading JetHERWIG



30 < ET(jet#1) < 70 GeV

"Transverse" Region Jet#1

Data - Theory: Charged Particle Density dN/dηηηηdφφφφ

-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y



30 < ET(jet#1) < 70 GeV PYTHIA Tune A

Jet#1

"Transverse" Region


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y



30 < ET(jet#1) < 70 GeV HERWIG

Jet#1

"Transverse" Region



�Leading Jet� PTsum Density: PY Tune A vs HERWIG


0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Leading JetPY Tune A

30 < ET(jet#1) < 70 GeVCharged Particles (|ηηηη|<1.0, PT>0.5 GeV/c)


Jet#1"Transverse" Region


0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Leading JetHERWIG



Jet#1

"Transverse" Region

Data - Theory: Charged PTsum Density dPT/dηηηηdφφφφ

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)



30 < ET(jet#1) < 70 GeV

PYTHIA Tune A

Jet#1

"Transverse" Region


-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)



30 < ET(jet#1) < 70 GeV HERWIG

Jet#1

"Transverse" Region



�Back-to-Back� Charge Density: PY Tune A vs HERWIG


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

Back-to-BackPY Tune A



"Transverse" Region

Jet#1


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

Back-to-BackHERWIG



"Transverse" Region

Jet#1


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y



30 < ET(jet#1) < 70 GeVBack-to-Back

PYTHIA Tune A

Jet#1

"Transverse" Region


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y




HERWIG

Jet#1

"Transverse" Region



�Leading Jet� PTsum Density: PY Tune A vs HERWIG


0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Back-to-BackPY Tune A



Jet#1"Transverse" Region


0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

) Back-to-BackHERWIG



Jet#1

"Transverse" Region


-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)




PYTHIA Tune A

Jet#1"Transverse"

Region


-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)




HERWIG

Jet#1"Transverse"

Region



�MAX/MIN Transverse� Charged Particle Densities


�Toward�

�TransMAX� �TransMIN�

Jet #2 Direction

�Away�

• Define the MAX and MIN �transverse� regions on an event-by-event basis with MAX (MIN) having the largest (smallest) density. Each of the two �transverse� regions have an area in ηηηη-φφφφ space of 4ππππ/6.

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

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


�Toward�


�Away�

Jet #1 Direction



�Toward�

�Away�

�Toward-Side� Jet

�Away-Side� Jet

Jet #3

�TransMIN� very sensitive to the �beam-beam remnants�! Area = 4ππππ/6



Transverse Densities: �Leading Jet� versus �Back-to-Back�

"AVE Transverse" Charge Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0.8

1.0

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity


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

Leading Jet

Back-to-Back

PY Tune A

HW

"MAX-MIN Transverse" Charge Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity


1.96 TeV

PY Tune A


Back-to-BackHW

LeadingJet

"AVE Transverse" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

PTs

um D

ensi

ty (G

eV/c

) CDF Preliminarydata uncorrectedtheory + CDFSIM


Back-to-Back

Leading Jet

PY Tune A

HW1.96 TeV

"MAX-MIN Transverse" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.5

1.0

1.5

2.0

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

PTs

um D

ensi

ty (G

eV/c

)


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

PY Tune A

HW

Back-to-Back

LeadingJet



Transverse Densities: �Leading Jet� versus �Back-to-Back�

"MIN Transverse" Charge Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity


1.96 TeV


Min-Bias

Back-to-Back

Leading Jet

"MIN Transverse" Charge Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity

HW


1.96 TeV


PY Tune A

Back-to-Back

Leading Jet

"MIN Transverse" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

PTs

um D

ensi

ty (G

eV/c

)


1.96 TeV


Min-BiasBack-to-Back

Leading Jet

"MIN Transverse" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

PTs

um D

ensi

ty (G

eV/c

)


1.96 TeV


PY Tune A

HW Back-to-Back

Leading Jet



�Transverse� PTmax: �Leading Jet� versus �Back-to-Back�

"Transverse" Charged PTmax

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 50 100 150 200 250

ET(jet#1) (GeV)"T

rans

vers

e" P

Tmax

(GeV

/c) CDF Preliminary

data uncorrected1.96 TeV


Min-Bias

Leading Jet

Back-to-Back

• Define PTmaxT on and event-by-event bases to be the higherst pT

charged particle (pT > 0.5 GeV/c, |ηηηη| < 1) in the �transverse� region. • Shows the the average PTmaxT versus ET(jet#1) for �back-to-back�

and �leading jet� events. • Also shows the average maximum pT charged particle, PTmax, for

�min-bias� collisions (pT > 0.5 GeV/c, |ηηηη| < 1).


�Toward�

�TransMIN� �TransMAX�

PTmaxT

Jet #2 Direction

�Away�


�Toward�

�TransMIN�

�Away�

�TransMAX�

PTmaxT



�Transverse� PTmax: PY Tune A versus HERWIG

"Transverse" Charged PTmax

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 50 100 150 200 250

ET(jet#1) (GeV)"T

rans

vers

e" P

Tmax

(GeV

/c) CDF Preliminary

data uncorrectedtheory + CDFSIM

1.96 TeV


Leading Jet

Back-to-BackHW

PY Tune A

• Define PTmaxT on and event-by-event bases to be the higherst pT

charged particle (pT > 0.5 GeV/c, |ηηηη| < 1) in the �transverse� region. • Shows the the average PTmaxT versus ET(jet#1) for �back-to-back�

and �leading jet� events compared with PYTHIA Tune A and HERWIG after CDFSIM.


�Toward�


PTmaxT

Jet #2 Direction

�Away�


�Toward�

�TransMIN�

�Away�

�TransMAX�

PTmaxT



�Leading Jet�: �Associated� Transverse Densities

"Transverse" Charged Particle Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0.8

1.0

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity


"transMAX"PTmaxT not included

AVE "Transverse"

"transMIN"CDF Preliminary

data uncorrected

Leading Jet

• Use the leading jet to define the �transverse� region and look at the

maximum PT charged particle in the �transverse� region, PTmaxT. Define �transMAX� to be the �transverse� region that contains PTmaxT and �transMIN� to be the other �transverse� region.

• Shows the �transMAX� and �transMIN� associated charged particle density, dN/dηηηηdφφφφ, for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) as a function of ET(jet#1) compared with the average �transverse� charged particle density.


�Toward�

�TransMIN�

�Away�

�TransMAX�

PTmaxT

�Associated� densities do not include PTmaxT!



�Leading Jet�: �Associated� Transverse Densities

"Transverse" Charged Particle Density: dN/dηηηηdφφφφ

0.0

0.2

0.4

0.6

0.8

1.0

0 50 100 150 200 250

ET(jet#1) (GeV)

"Tra

nsve

rse"

Cha

rge

Den

sity



AVE "Transverse"

"transMIN"CDF Preliminary

data uncorrected

Leading Jet



• Shows the �transMAX� and �transMIN� associated charged particle density, dN/dηηηηdφφφφ, for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) as a function of ET(jet#1) compared with the average �transverse� charged particle density.


�Toward�

�TransMIN�

�Away�

�TransMAX�

PTmaxT


It is more probable to find a particle accompying PTmaxT than it is to find a particle in

the �transverse� region!



�Leading Jet�: �Associated� Transverse PTsum Density

"Transverse" Charged PTsum Density: dPT/dηηηηdφφφφ

0.0

0.4

0.8

1.2

1.6

0 50 100 150 200 250

ET(jet#1) (GeV)

Char

ged

PTsu

m D

ensi

ty (

GeV

/c) CDF Preliminary

data uncorrected


AVE "Transverse"

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

Leading Jet



• Shows the �transMAX� and �transMIN� associated charged PTsum density, dPT/dηηηηdφφφφ, for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) as a function of ET(jet#1) compared with the average �transverse� charged particle density.


�Toward�

�TransMIN�

�Away�

�TransMAX�

PTmaxT




�Associated� Transverse Densities: PY Tune A vs HERWIG

"Associated TransMAX" Charge Density: dN/dηηηηdφφφφ

0.0

0.6

1.2

1.8

2.4

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rge

Parti

cle

Den

sity


PYTHIA Tune A 1.96 TeV


PTmaxT not includedPTmaxT > 0.5 GeV/c

PTmaxT > 2 GeV/c

Leading Jet

"Associated TransMAX" Charge Density: dN/dηηηηdφφφφ

0.0

0.6

1.2

1.8

2.4

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rge

Parti

cle

Den

sity


HERWIG



PTmaxT > 2 GeV/c

Leading Jet

"Associated TransMIN" Charge Density: dN/dηηηηdφφφφ

0.0

0.4

0.8

1.2

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rge

Parti

cle

Den

sity




PTmaxT > 2 GeV/c

PTmaxT > 0.5 GeV/c

Leading Jet

"Associated TransMIN" Charge Density: dN/dηηηηdφφφφ

0.0

0.4

0.8

1.2

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rge

Parti

cle

Den

sity


HERWIG 1.96 TeV


PTmaxT > 2 GeV/c

PTmaxT > 0.5 GeV/c

Leading Jet



�Associated� Transverse Densities: PY Tune A vs HERWIG

"Associated TransMAX" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.6

1.2

1.8

2.4

3.0

3.6

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rged

PTs

um D

ensi

ty (G

eV/c





PTmaxT > 2 GeV/c

Leading Jet

"Associated TransMAX" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.6

1.2

1.8

2.4

3.0

3.6

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rged

PTs

um D

ensi

ty (G

eV/c


HERWIG 1.96 TeV



PTmaxT > 2 GeV/c

Leading Jet

"Associated TransMIN" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.5

1.0

1.5

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rged

PTs

um D

ensi

ty (G

eV/c




PTmaxT > 0.5 GeV/c

PTmaxT > 2 GeV/c

Leading Jet

"Associated TransMIN" PTsum Density: dPT/dηηηηdφφφφ

0.0

0.5

1.0

1.5

0 50 100 150 200 250

ET(jet#1) (GeV)

Cha

rged

PTs

um D

ensi

ty (G

eV/c


HERWIG 1.96 TeV


PTmaxT > 0.5 GeV/c

PTmaxT > 2 GeV/c

Leading Jet



Back-to-Back: �Associated� Charge Densities ∆φ ∆φ ∆φ ∆φ Dependence


PTmaxT Direction

Jet#1 Region

Jet#2 Region

• Use the leading jet in �back-to-back� events to define the �transverse� region and look at the maximum pT charged particle in the �transverse� region, PTmaxT.

• Look at the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle and PTsum densities, dN/dηηηηdφφφφ and dPT/dηηηηdφφφφ for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT.

• Rotate so that PTmaxT is at the center of the plot (i.e. 180o).


�Toward�


PTmaxT

Jet #2 Direction

�Away�


Jet#1 Region

PTmaxT Direction

Jet#2 Region




Back-to-Back: �Associated� Charge Density ∆φ ∆φ ∆φ ∆φ Dependence

Associated Particle Density: dN/dηηηηdφφφφ

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 30 60 90 120 150 180 210 240 270 300 330 360

∆φ∆φ∆φ∆φ (degrees)A

ssoc

iate

d Pa

rtic

le D

ensi

ty

PTmaxT > 2.0 GeV/cPTmaxT > 1.0 GeV/cPTmaxT > 0.5 GeV/c


PTmaxT

30 < ET(jet#1) < 70 GeV


PTmaxT not included

"Jet#1" Region

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for PTmaxT > 0.5 GeV/c, PTmaxT > 1.0 GeV/c and PTmaxT > 2.0 GeV/c, for �back-to-back� events with 30 < ET(jet#1) < 70 GeV.

• Shows �jet structure� in the �transverse� region (i.e. the �birth� of the third jet).


PTmaxT Direction

Jet#1 Region

Jet#2 Region






0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 30 60 90 120 150 180 210 240 270 300 330 360


ssoc

iate

d Pa

rtic

le D

ensi

ty



PTmaxT

30 < ET(jet#1) < 70 GeV


PTmaxT not included

"Jet#1" Region

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for PTmaxT > 0.5 GeV/c, PTmaxT > 1.0 GeV/c and PTmaxT > 2.0 GeV/c, for �back-to-back� events with 30 < ET(jet#1) < 70 GeV.


PTmaxT Direction

Jet#1 Region

Jet#2 Region






0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360

∆φ∆φ∆φ∆φ (degrees)C

harg

ed P

artic

le D

ensi

ty

Back-to-BackPTmaxT > 0.5 GeV/c



"Transverse" Region

PTmaxT Jet#1

Associated DensityPTmaxT not included

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV.

• Shows ∆φ∆φ∆φ∆φ dependence of the charged particle density, dN/dηηηηdφφφφ (pT > 0.5 GeV/c, |ηηηη| < 1) relative to jet#1 (rotated to 270o) for �back-to-back events� with 30 < ET(jet#1) < 70 GeV.


Jet#1 Region

PTmaxT Direction

Jet#2 Region


�Toward�


�Away�

Jet #2 Direction

Log Scale





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


harg

ed P

artic

le D

ensi

ty




"Transverse" Region

PTmaxT Jet#1





Jet#1 Region

PTmaxT Direction

Jet#2 Region


�Toward�


�Away�

Jet #2 Direction

Log Scale

It is more probable to find a particle accompying PTmaxT than it is to find a particle in

the �transverse� region!





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


harg

ed P

artic

le D

ensi

ty




"Transverse" Region

PTmaxT Jet#1





Jet#1 Region

PTmaxT Direction

Jet#2 Region


�Toward�


�Away�

Jet #2 Direction

Log Scale

Interesting correlations opposite to PTmaxT!





6 10 1418

2226

3034

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

102

106

110

114

118

122

126

130

134

138

142

146

150154

158162

166170174178

182186190194

198202

206210

214

218

222

226

230

234

238

242

246

250

254

258

262

266

270

274

278

282

286

290

294

298

302

306

310

314

318

322

326

330334

338342

346350 354 358




"Transverse" Region "Transverse"

Region

Jet#1


PTmaxT

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) and the charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1) relative to jet#1 (rotated to 270o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV.


�Toward�


�Away�

Jet #2 Direction


Jet#1 Region

PTmaxT Direction

Jet#2 Region





6 10 1418

2226

3034

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

102

106

110

114

118

122

126

130

134

138

142

146

150154

158162

166170174178

182186190194

198202

206210

214

218

222

226

230

234

238

242

246

250

254

258

262

266

270

274

278

282

286

290

294

298

302

306

310

314

318

322

326

330334

338342

346350 354 358





Region

Jet#1


PTmaxT

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) and the charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1) relative to jet#1 (rotated to 270o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV.


�Toward�


�Away�

Jet #2 Direction


Jet#1 Region

PTmaxT Direction

Jet#2 Region





6 10 1418

2226

3034

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

102

106

110

114

118

122

126

130

134

138

142

146

150154

158162

166170174178

182186190194

198202

206210

214

218

222

226

230

234

238

242

246

250

254

258

262

266

270

274

278

282

286

290

294

298

302

306

310

314

318

322

326

330334

338342

346350 354 358





Region

Jet#1

Associated DensityPTmaxT > 2 GeV/c

(not included)

PTmaxT

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (PT > 0.5 GeV/c, |ηηηη| < 1, PTmaxT > 2 GeV/c, not including PTmaxT) relative to PTmaxT (rotated to 180o) and the charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1) relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV.


�Toward�


�Away�

Jet #2 Direction


Jet#1 Region

PTmaxT Direction

Jet#2 Region





6 10 1418

2226

3034

38

42

46

50

54

58

62

66

70

74

78

82

86

90

94

98

102

106

110

114

118

122

126

130

134

138

142

146

150154

158162

166170174178

182186190194

198202

206210

214

218

222

226

230

234

238

242

246

250

254

258

262

266

270

274

278

282

286

290

294

298

302

306

310

314

318

322

326

330334

338342

346350 354 358





Region

Jet#1

Associated DensityPTmaxT > 2 GeV/c

(not included)

PTmaxT

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density, dN/dηηηηdφφφφ, (PT > 0.5 GeV/c, |ηηηη| < 1, PTmaxT > 2 GeV/c, not including PTmaxT) relative to PTmaxT (rotated to 180o) and the charged particle density, dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1) relative to jet#1 (rotated to 270o) for 30 < ET(jet#1) < 70 GeV.


�Toward�


�Away�

Jet #2 Direction


Jet#1 Region

PTmaxT Direction

Jet#2 Region



Back-to-Back: �Associated� Charge Densities ∆φ ∆φ ∆φ ∆φ Dependence


0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Asso

ciat

ed P

artic

le D

ensi

ty



PTmaxT

30 < ET(jet#1) < 70 GeV


PTmaxT not included

"Jet#1" Region

Associated PTsum Density: dPT/dηηηηdφφφφ

0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Asso

ciat

ed P

Tsum

Den

sity

(GeV

/c)



30 < ET(jet#1) < 70


"Jet#1" Region

PTmaxT

PTmaxT not included


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Char

ged

Parti

cle

Dens

ity




"Transverse" Region

PTmaxT Jet#1



0.1

1.0

10.0

100.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Char

ged

PTsu

m D

ensi

ty (G

eV/c

)




"Transverse" Region

Jet#1PTmaxTAssociated DensityPTmaxT not included



�Min-Bias� Associated Charged Particle Density


0.0

0.1

0.2

0.3

0.4

0.5

0 30 60 90 120 150 180 210 240 270 300 330 360


harg

ed P

artic

le D

ensi

ty

PTmax

Associated DensityPTmax not included



Charge Density

Min-Bias

• Use the maximum pT charged particle in the event, PTmax, to define a

direction and look at the �associated� density, dN/dηηηηdφ.φ.φ.φ. • Shows the data on the ∆φ∆φ∆φ∆φ dependence of the �associated� charged

particle density, dN/dηηηηdφφφφ, for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmax) relative to PTmax (rotated to 180o) for �min-bias� events. Also shown is the average charged particle density, dN/dηηηηdφφφφ, for �min-bias� events.

PTmax Direction

Correlations in φφφφ


�Associated� densities do not include PTmax!



�Min-Bias� Associated Charged Particle Densities


0.0

0.2

0.4

0.6

0.8

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity

PTmax > 2.0 GeV/cPTmax > 1.0 GeV/cPTmax > 0.5 GeV/c


PTmaxPTmax not included


Min-Bias


0.0

0.2

0.4

0.6

0.8

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)

PTmax > 2.0 GeV/cPTmax > 1.0 GeV/cPTmax > 0.5 GeV/c

PTmax



PTmax not included Min-Bias


0.0

0.1

0.2

0.3

0.4

0.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

Par

ticle

Den

sity

PTmax




Charge Density

Min-Bias


0.0

0.1

0.2

0.3

0.4

0.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Cha

rged

PTs

um D

ensi

ty (G

eV/c

)

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


PTsum Density


Min-Bias



�Min-Bias� Associated Charge Densities vs PY Tune A


0.0

0.2

0.4

0.6

0.8

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity

PTmax > 2.0 GeV/cPY Tune APTmax > 0.5 GeV/cPY Tune A


PTmaxPTmax not included (|ηηηη|<1.0, PT>0.5 GeV/c)

PY Tune A 1.96 TeV


0.0

0.2

0.4

0.6

0.8

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

) PTmax > 2.0 GeV/cPY Tune APTmax > 0.5 GeV/cPY Tune A

PTmax


(|ηηηη|<1.0, PT>0.5 GeV/c) PTmax not included

PY Tune A 1.96 TeV

• Shows the data on the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle and PTsum density, dN/dηηηηdφφφφ and dPT/dηηηηdφ,φ,φ,φ, for charged particles (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmax) relative to PTmax (rotated to 180o) for �min-bias� events with PTmax > 0.5 GeV/c and PTmax > 2.0 GeV/c compared with PYTHIA Tune A (�min-bias�).

• PYTHIA Tune A (�min-bias�) predicts slightly too much �hard scattering� in �min-bias� collisions (i.e. it does not have exactly the right �hard� versus �soft� mixture).



�Associated� Charge Density: �Back-to-Back� vs �Min-Bias�


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


ssoc

iate

d Pa

rtic

le D

ensi

ty

PTmaxT > 2.0 GeV/cPTmax > 2.0 GeV/c


30 < ET(jet#1) < 70 GeV

PTmaxTPTmax

PTmaxT, PTmax not includedCDF Preliminary

data uncorrected

Min-Bias

• Shows the ∆φ∆φ∆φ∆φ dependence of the �associated� charged particle density,

dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV and PTmaxT > 2.0 GeV/c and for �min-bias� collisions relative to PTmax (rotated to 180o) with PTmax > 2.0 GeV/c.

PTmax Direction




PTmaxT Direction

Jet#1 Region

Jet#2 Region

Log Scale





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


ssoc

iate

d Pa

rtic

le D

ensi

ty



30 < ET(jet#1) < 70 GeV

PTmaxTPTmax


data uncorrected

Min-Bias


dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV and PTmaxT > 2.0 GeV/c and for �min-bias� collisions relative to PTmax (rotated to 180o) with PTmax > 2.0 GeV/c.

PTmax Direction




PTmaxT Direction

Jet#1 Region

Jet#2 Region

Log Scale

�Birth� of jet#3 in the �transverse� region!

�Birth� of jet#1 in �min-bias� collisions!





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


ssoc

iate

d Pa

rtic

le D

ensi

ty




PTmaxTPTmax

PTmaxT, PTmax not included

30 < ET(jet#1) < 70 GeV

Min-Bias x 1.65


dN/dηηηηdφφφφ, (pT > 0.5 GeV/c, |ηηηη| < 1, not including PTmaxT) relative to PTmaxT (rotated to 180o) for �back-to-back� events with 30 < ET(jet#1) < 70 GeV and PTmaxT > 2.0 GeV/c and for �min-bias� collisions (times 1.65) relative to PTmax (rotated to 180o) with PTmax > 2.0 GeV/c.

PTmax Direction




PTmaxT Direction

Jet#1 Region

Jet#2 Region

Log Scale

x 1.65



Associated Densities: �Back-to-Back� versus �Min-Bias�


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity



30 < ET(jet#1) < 70 GeV

PTmaxTPTmax


data uncorrected

Min-Bias


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)

PTmaxT > 2.0 GeV/cPTmax > 2.0 GeV/c CDF Preliminary

data uncorrectedPTmaxPTmaxT



30 < ET(jet#1) < 70 GeV

Min-Bias


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity




PTmaxTPTmax


30 < ET(jet#1) < 70 GeV

Min-Bias x 1.65


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)

PTmaxT > 2.0 GeV/cPTmax > 2.0 GeV/c CDF Preliminary

data uncorrectedPTmaxPTmaxT



30 < ET(jet#1) < 70 GeV

Min-Bias x 1.65



�Back-to-Back� Associated Densities: PY Tune A vs HERWIG


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity

PTmaxT > 0.5 GeV/cPY Tune A



PTmaxT

CDF Preliminarydata uncorrectedtheory + CDFSIM PTmaxT not included

"Jet#1" Region


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity

PTmaxT > 0.5 GeV/cHERWIG



PTmaxT


"Jet#1" Region

Data - Theory: Associated Particle Density dN/dηηηηdφφφφ

-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y



30 < ET(jet#1) < 70 GeVBack-to-BackPYTHIA Tune A

PTmaxT "Jet#1" RegionPTmaxT not included


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y



30 < ET(jet#1) < 70 GeVBack-to-BackHERWIG

PTmaxT "Jet#1" RegionPTmaxT not included





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)





PTmaxT "Jet#1" Region

PTmaxT not included


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)






PTmaxT not included

Data - Theory: Associated PTsum Density dPT/dηηηηdφφφφ

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)




PYTHIA Tune A

PTmaxT

PTmaxT not included

"Jet#1" Region

Data - Theory: Associated PTsum Density dPT/dηηηηdφφφφ

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y (G

eV/c

)




HERWIG

PTmaxT

PTmaxT not included

"Jet#1" Region





0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity




PTmaxT


"Jet#1" Region


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

Part

icle

Den

sity




PTmaxT


"Jet#1" Region


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y





PTmaxT > 2.0 GeV/c (not included)


-1.0

-0.5

0.0

0.5

1.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Dat

a - T

heor

y










0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)






PTmaxT not included


0.1

1.0

10.0

0 30 60 90 120 150 180 210 240 270 300 330 360


Ass

ocia

ted

PTsu

m D

ensi

ty (G

eV/c

)






PTmaxT not included


-2.5-2.0-1.5-1.0-0.50.00.51.01.5

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Summary & Conclusios

• By selecting events with at least two jets that are nearly back-to-back we are able to look closer at the �beam-beam remnant� and multiple parton interaction components of the �underlying event�. PYTHIA Tune A (with multiple parton interactions) does a good job in describing the �underlying event� (i.e. �transverse� regions) for both �leading jet� and �back-to-back� events. HERWIG (without multiple parton interactions) does not have enough activity in the �underlying event� for ET(jet#1) less than about 150 GeV, which was also observed in our published Run 1 analysis.

• To examine the �jet� structure in the �underlying event� we define �associated� charged particle densities that measure the number of charged particles and scalar pT sum of charged particles accompanying the maximum pT charged particle in the �transverse� region, PTmaxT. The data show strong correlations. For ET(jet#1) greater than about 50 GeV there is a higher density of charged particles �associated� with PTmaxT (not including PTmaxT) in the �transMAX� region than there is in the average �transverse� region. These correlations indicate �jet� structure in the �underlying event� (i.e. �transverse� region) at PTmaxT values as low as 1.0 GeV/c!

Documents

Rick Field November 11, 2003 A Closer Look at the ...rfield/cdf/CDF_topmass_11-11-03.pdf · Rick Field November 11, 2003 CDF Top Mass Workshop Page 2 of 46 The ﬁTransverseﬂ Region