Cosmic QCD 2013

Cosmic QCD 2013 LPTHE Paris, May 15, 2013

Rick Field – Florida/CDF/CMS Page 1

Rick FieldUniversity of Florida

Outline of Talk

CMS at the LHCCDF Run 2

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

Cosmic QCD 2013Cosmic QCD 2013

New CDF UE data from the Tevatron Energy Scan.

New CMS UE data.

Comparisons with PYTHIA 6.4 Tune Z1.

New UE-MB comparisons!

Summary & Conclusions.

Energy Dependence of the “Underlying Event”

Proton AntiProton

PT(hard)

Outgoing Parton

Outgoing Parton

Underlying Event Underlying Event

Initial-State Radiation

Final-State Radiation

Mapping out the energy dependence: Tevatron to the LHC!

New CDF MB data.



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



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

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

PTmax Direction

“Toward”

“Transverse” “Transverse”

“Away”

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

“Transverse” Charged Particle Average PT: Event-by-event <pT> = PTsum/Nchg for charged particles (pT > 0.5 GeV/c, || < cut) in the “transverse” region as defined by the leading charged particle, PTmax, averaged over all events with at least one particle in the “transverse” region with pT > 0.5 GeV/c, || < cut.

Zero “Transverse” Charged Particles: If there are no charged particles in the “transverse” region then Nchg and PTsum are zero and one includes these zeros in the average over all events with at least one particle with pT > 0.5 GeV/c, || < cut. However, if there are no charged particles in the “transverse” region then the event is not used in constructing the “transverse” average pT.

cut = 1.0 and cut = 0.8



UE ObservablesUE Observables “Toward” Charged Particle Density: Number of charged particles (pT

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

PTmax Direction

“Toward”


“Away”

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

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

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

cut = 0.8



UE ObservablesUE Observables Overall “Associated” Charged Particle Density: Number of

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

PTmax Direction

“Toward”


“Away”

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

Note: The overall “associated” density is equal to the average of the “Towards”, “Away”, and “Transverse” densities.

Overall “Associated” Density = (“Towards” Density + “Away” Density + “Transverse” Density)/3

cut = 0.8



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

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

PTmax Direction

“Toward”

“TransMAX” “TransMIN”

“Away”

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

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

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

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

cut = 0.8



““transMIN” & “transDIF”transMIN” & “transDIF” The “toward” region contains the leading “jet”, while the “away”

region, on the average, contains the “away-side” “jet”. The “transverse” region is perpendicular to the plane of the hard 2-to-2 scattering and is very sensitive to the “underlying event”. For events with large initial or final-state radiation the “transMAX” region defined contains the third jet while both the “transMAX” and “transMIN” regions receive contributions from the MPI and beam-beam remnants. Thus, the “transMIN” region is very sensitive to the multiple parton interactions (MPI) and beam-beam remnants (BBR), while the “transMAX” minus the “transMIN” (i.e. “transDIF”) is very sensitive to initial-state radiation (ISR) and final-state radiation (FSR).

“TransDIF” density more sensitive to ISR & FSR.

PTmax Direction

“TransMAX” “TransMIN”

“Toward”

“Away”

“Toward-Side” Jet

“Away-Side” Jet

Jet #3

“TransMIN” density more sensitive to MPI & BBR.

0 ≤ “TransDIF” ≤ 2×”TransAVE”

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

Question: Do you expect the energy dependence of the “transMIN” and “transDIF” densities to be the same? Or do you expect that one of the two densities will increase faster with increasing energy than the other? Which one and why?



Overall “Associated” DensityOverall “Associated” Density

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

Overall "Associated" Density

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CDF PreliminaryCorrected Data

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

PTsum (GeV/c)

Nchg


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CDF Preliminary corrected data

Tune Z1 generator level


PTsum (GeV/c)

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Nchg


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PTsum (GeV/c)

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PTsum (GeV/c)

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The data are compared with PYTHIA Tune Z1.



Overall “Associated” DensityOverall “Associated” Density

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

Overall "Associated" Charged Particle Density

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CDF PreliminaryCorrected Data 1.96 TeV

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Overall "Associated" PTsum Density

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CDF Preliminary Corrected Data

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Overall Associated PTsum Density

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Overall Associated Nchg Density

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““Associated” Charged Particle DensityAssociated” Charged Particle Density

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

"Associated" Charged Particle Density: dN/dd

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"Away"

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"Transverse"



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Associated Charged Particle Density: dN/dd

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"Away"

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300 GeV

"Transverse"




““Associated” Charged Particle DensityAssociated” Charged Particle Density

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

"Toward" Charged Particle Density: dN/dd

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"Away" Charged Particle Density: dN/dd

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"Transverse" Charged Particle Density: dN/dd

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CDF Preliminary Corrected Data 1.96 TeV

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"Toward" Charged Particle Density: dN/dd

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"Away" Charged Particle Density: dN/dd

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““Associated” Charged PTsum DensityAssociated” Charged PTsum Density

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

"Associated" Charged PTsum Density: dPT/dd

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PT

sum

Den

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(G

eV/c

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"Away"

"Toward"

1.96 TeV

"Transverse"



0.0

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PT

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"Away""Toward"

900 GeV

"Transverse"



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PT

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"Toward"300 GeV

"Transverse"



Associated Charged PTsum Density: dPT/dd

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"Away""Toward"

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““Toward” Associated DensityToward” Associated Density

At low center-of-mass energies PTmax carries almost all the momentum of the “toward” parton (i.e. z ≈ 1) leaving very little momentum for the other particles in the “jet”.

“Toward” Parton“Away” Parton

“PTmax” Particle

300 GeV

“Associated” Toward Particles

“Away” Particles



““Toward” Associated DensityToward” Associated Density

At higher center-of-mass energies the same PTmax carries less of the momentum of the “toward” parton (i.e. z < 1) leaving more momentum for the other particles in the “jet”.

“Toward” Parton“Away” Parton

“PTmax” Particle

1.96 TeV

“Associated” Toward Particles

“Away” Particles



““Associated” Charged PTsum DensityAssociated” Charged PTsum Density

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

"Toward" Charged PTsum Density: dPT/dd

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"To

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"Away" Charged PTsum Density: dPT/dd

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900 GeV

"Transverse" Charged PTsum Density: dPT/dd

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"Toward" Charged PTsum Density: dPT/dd

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PT

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/c) CDF Preliminary

corrected dataTune Z1 generator level


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"Away" Charged PTsum Density: dPT/dd

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““transMAX/MIN” NchgDentransMAX/MIN” NchgDen

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


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"TransMIN"

"TransMAX"

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"TransMIN"

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corrected data


"TransMIN"

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300 GeV



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"TransMIN"

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"TransMIN"

"TransMAX"

300 GeV



““transDIF/AVE” NchgDentransDIF/AVE” NchgDen

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


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300 GeV

"TransDIF"

"TransAVE"



““transMAX/MIN” NchgDentransMAX/MIN” NchgDen

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

"TransMAX" Charged Particle Density: dN/dd

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"TransMIN" Charged Particle Density: dN/dd

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"TransDIF" Charged Particle Density: dN/dd

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““transMAX/MIN” PTsumDentransMAX/MIN” PTsumDen

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


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““transDIF/AVE” PTsumDentransDIF/AVE” PTsumDen

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


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"TransDIF"

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““transMAX/MIN” PTsumDentransMAX/MIN” PTsumDen

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

"TransMAX" Charged PTsum Density: dPT/dd

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"TransMIN" Charged PTsum Density: dPT/dd

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"TransDIF" Charged PTsum Density: dPT/dd

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"TransMAX" Charged PTsum Density: dPT/dd

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"TransMIN" Charged PTsum Density: dPT/dd

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"TransDIF" Charged PTsum Density: dPT/dd

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““transMAX” NchgDen vs EtransMAX” NchgDen vs Ecmcm

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


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5.0 < PTmax < 6.0 GeV/c

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



““transMIN” NchgDen vs EtransMIN” NchgDen vs Ecmcm

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

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


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““transDIF” NchgDen vs EtransDIF” NchgDen vs Ecmcm

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

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


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““Transverse” NchgDen vs ETransverse” NchgDen vs Ecmcm

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


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"Transverse" Charged Particle Density Ratio

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Divided by 300 GeV Value



5.0 < PTmax < 6.0 GeV/c

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



““Transverse” PTsumDen vs ETransverse” PTsumDen vs Ecmcm

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

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


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Ch

arg

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"TransMIN"

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"Transverse" Charged PTsum Density Ratio

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Divided by 300 GeV ValueCharged Particles (||<0.8, PT>0.5 GeV/c)


5.0 < PTmax < 6.0 GeV/c



““TransMAX/MIN” vs ETransMAX/MIN” vs Ecmcm

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


0.0

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(G

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"TransMIN"

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5.0 < PTmax < 6.0 GeV/c


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Ch

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"TransMIN"

"TransMAX"

5.0 < PTmax < 6.0 GeV/c

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



““TransDIF/AVE” vs ETransDIF/AVE” vs Ecmcm"Transverse" Charged Particle Density: dN/dd

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(G

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"TransDIF"

"TransAVE"

5.0 < PTmax < 6.0 GeV/c

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

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



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

Ratio of CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged particle density in the “transMIN”, and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6.4 Tune Z1.


1.0

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Pa

rtic

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"TransDIF"

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Ratio of CDF data at 1.96 TeV, 900 GeV, and 300 GeV to the value at 300 GeV for the charged PTsum density in the “transMIN”, and “transDIF” regions as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8 with 5 < PTmax < 6 GeV/c. The data are plotted versus the center-of-mass energy (log scale). The data are compared with PYTHIA 6.4 Tune Z1.

Answer to QuestionThe “transMIN” (MPI-BBR component) increases

much faster with center-of-mass energy than the “transDIF” (ISR-FSR component)!

Duh!!



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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““Tevatron” to the LHCTevatron” to the LHC"Transverse" Charged Particle Density: dN/dd

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Charged Particles (PT>0.5 GeV/c)

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PYTHIA Tune Z1

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CDFCDF

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““Tevatron” to the LHCTevatron” to the LHC"Transverse" Charged PTsum Density: dPT/dd

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PYTHIA Tune Z1


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

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

Pseudo-Rapidity Distribution: dN/d

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CDF versus CMSCDF versus CMSPseudo-Rapidity Distribution: dN/d

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CDF and CMS data at 900 GeV on the pseudo-rapidity distribution, dN/d, for charged with pT > 0.5 GeV/c and || < 0.8 for events with at least one charged particle with pT > 0.5 GeV/c and || < 0.8. The data are corrected to the particle level with errors that include both the statistical error and the systematic uncertainty.

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


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900 GeVCDF red squaresCMS black dots

CDF slightly higher than CMS!

CDF slightly higher than CMS!


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Overall Charged Particle DensityOverall Charged Particle DensityPseudo-Rapidity Distribution: dN/d

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Ecm Nchg error NchgDen error

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1.96 TeV 3.439 0.186 0.342 0.019

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dNNchg

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

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

Overall Charged Particle Density

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MB versus the UEMB versus the UE

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Corrected CDF and CMS data on the charged particle density ratio, in the “transverse” region as defined by the leading charged particle (PTmax) for charged particles with pT > 0.5 GeV/c and || < 0.8. The ratio corresponds to the “transverse” charged particle density divided by the overall charged particle density.

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

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Summary & ConclusionsSummary & Conclusions The “transMIN” (MPI-BBR component) increases much faster with

center-of-mass energy than the “transDIF” (ISR-FSR component)! Previously we only knew the energy dependence of “transAVE”.

The “transverse” (i.e. “transAVE”) increases faster with center-of-mass energy than the overall charged density (Nchg ≥ 1)!

Soon we will have at lot of 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!

Documents

Cosmic QCD 2013