[PPT] - Particle spectra in Minimum Bias events at 13TeV Juan Manuel Grados PowerPoint Presentation

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Particle spectra in Minimum Bias events at 13TeV

Juan Manuel Grados Luyando on behalf of the CMS collaboration

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Deutsches Elektronen-Synchrotron, Hamburg MPI@LHC 2015 Trieste, Italy

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Motivation

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Probe the different components of hadron production

The transition from the perturbative to the non-perturbative region Behaviour of QCD at small-x Multiple parton interactions Saturation of parton densities Soft diffractive components

Tune the modeling of these contributions

Center-of-mass energy dependence Taming of the cross section in the low pT region

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Multiple Parton Interactions

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Multiple Parton Interactions Soft to semi-hard interactions Phenomenological models Tuning of the model parameters based

n experimental data

Comparison to the new CMS tunes Simultaneous fits to CDF UE data at 0.9 and 1.96 TeV, and CMS UE at 7 TeV Energy dependence of the MPI parameters Different parton densities Theoretical uncertainties from allowed parameter space

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Pseudorapidity at 0T

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

0.01 0.02 0.03 0.04 0.05 0.06 10 20 30 40 50 fraction number of reconstructed tracks pp  √s = 13 TeV CMS data

PYTHIA8 CUETP8M1

EPOS LHC

Phys. Lett. B 751 (2015) 143–163
Measurement of pseudorapidity distribution of charged hadrons in proton-proton

collisions at √s = 13 TeV

Presented for inelastic events
No minimum transverse momentum requirement (measurement done at 0T)
Corrected to primary long-lived charged hadrons (no leptons)

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Measurement of pseudorapidity distribution of charged hadrons in proton-proton

collisions at √s = 13 TeV

Presented for inelastic events
No minimum transverse momentum requirement (measurement done at 0T)
Corrected to primary long-lived charged hadrons (no leptons)

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Pseudorapidity at 0T

Phys. Lett. B 751 (2015) 143–163

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

PHYTHIA8 (CUETP8M1 and CUETP8S1) and EPOS LHC agree with the measurement within the error bands

Data CUETP8S1-CTEQ6L1 CUETP8M1 PYTHIA8 Tune 4C 1 2 3 4 5 6 7 8 9

Charged-particle multiplicity, √s = 13 TeV dNch/dη

2
1.5
1
0.5

0.5 1 1.5 2 0.8 0.85 0.9 0.95 1.0 1.05 1.1 1.15

η

MC/Data

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Pseudorapidity at 0T

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

PHYTHIA8 (CUETP8M1 and CUETP8S1) and EPOS LHC agree with the measurement within the error bands

Phys. Lett. B 751 (2015) 143–163
Measurement of pseudorapidity distribution of charged hadrons in proton-proton

collisions at √s = 13 TeV

Presented for inelastic events
No minimum transverse momentum requirement (measurement done at 0T)
Corrected to primary long-lived charged hadrons (no leptons)

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Measurement of pseudorapidity distribution of charged particles in proton-proton

collisions at √s = 8 TeV

Presented for different diffractive event selections (TOTEM event selection)
Corrected down to zero transverse momentum
Corrected to all charged particles

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Pseudorapidity at 8 TeV

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

1 2 3 4 5 6

η /d

ch

dN

2 3 4 5 6 7 8

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b µ = 8 TeV, L = 45 s CMS-TOTEM, Inclusive pp <-5.3 η <6.5 or -6.5< η 1 in 5.3< ≥

ch

N Data Pythia6 Z2* Pythia8 4C Herwig++ EE3-CTEQ6L1 EPOS LHC QGSJetII-04

| η |

1 2 3 4 5 6

MC / Data

0.8 1 1.2

1 2 3 4 5 6

η /d

ch

dN

2 3 4 5 6 7 8

1

b µ = 8 TeV, L = 45 s CMS-TOTEM, NSD-enhanced pp

<-5.3 η <6.5 and -6.5< η 1 in 5.3< ≥

ch

N Data Pythia6 Z2* Pythia8 4C Herwig++ EE3-CTEQ6L1 EPOS LHC QGSJetII-04

| η |

1 2 3 4 5 6

MC / Data

0.8 1 1.2

1 2 3 4 5 6

η /d

ch

dN

1 2 3 4 5

1

b µ = 8 TeV, L = 45 s CMS-TOTEM, SD-enhanced pp <-5.3 η <6.5 or only -6.5< η 1 in only 5.3< ≥

ch

N Data Pythia6 Z2* Pythia8 4C Herwig++ EE3-CTEQ6L1 EPOS LHC QGSJetII-04

| η |

1 2 3 4 5 6

MC / Data

1 1.5

Eur. Phys. J. C (2014) 74:3053

TOTEM acceptance: 5.3 < |η| < 6.4

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Measurement of pseudorapidity distribution of charged particles in proton-proton

collisions at √s = 8 TeV

Presented for different diffractive event selections (TOTEM event selection)
Corrected down to zero transverse momentum
Corrected to all charged particles

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Pseudorapidity at 8 TeV

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Results after tuning

Eur. Phys. J. C (2014) 74:3053

CMS+TOTEM data CUETP6S1 CUETP8S1-CTEQ6L1 CUETP8S1-HERAPDF1.5LO CUETP8M1 1 2 3 4 5 6 7 8 9

CMS+TOTEM, dNch/d(|η|) √s = 8 TeV, Inclusive pp (dNch)/d(|η|)

1 2 3 4 5 6 0.6 0.8 1 1.2 1.4

|η|

MC/data CMS+TOTEM data CUETP6S1 CUETP8S1-CTEQ6L1 CUETP8S1-HERAPDF1.5LO CUETP8M1 1 2 3 4 5 6 7 8 9

CMS+TOTEM, dNch/d(|η|) √s = 8TeV, NSD-enhanced (dNch)/d(|η|)

1 2 3 4 5 6 0.6 0.8 1 1.2 1.4

|η|

MC/data CMS+TOTEM data CUETP6S1 CUETP8S1-CTEQ6L1 CUETP8S1-HERAPDF1.5LO CUETP8M1 1 2 3 4 5

CMS+TOTEM, dNch/d(|η|) √s = 8 TeV, SD-enhanced (dNch)/d(|η|)

1 2 3 4 5 6 0.6 0.8 1 1.2 1.4

|η|

MC/data

TOTEM acceptance: 5.3 < |η| < 6.4

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Event selection

Non-Single Diffractive enhanced: at least one particle with E>5GeV on each side. Single Diffractive enhanced: at least one particle with E>5GeV on one side. Other side no particle with E>5GeV. Inelastic enhanced: at least one particle on either side with E>5GeV.

Pseudorapidity Predictions

Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

We can implement a similar event selection but instead of TOTEM we use particles in the range 3 < |η| < 5 (HF calorimeter) in the following way:

Particle selection

2.4 < |η| < 2.4 (Tracker acceptance)

pT > 500MeV Final State Charged particles

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Pseudorapidity at 3.8T and diffractive events. Predictions

T h e s h a p e o f a l l t h e predictions for the inclusive and inelastic selections is very similar, only changing the predicted value by ~0.5 particles per η unit. For the SD selection: PYTHIA8 Tunes predict s i g n i fi c a n t l y d i f f e r e n t behaviour than EPOS-LHC. For the NSD selection: PYTHIA8 Tunes predict the same shape with different values, while EPOS-LHC has a valley in the central region.

P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 0.5 1 1.5 2 2.5 3 3.5 4 Selection: inclusive pp

1 N dN dη

2
1.5
1
0.5

0.5 1 1.5 2 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 η MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 0.5 1 1.5 2 2.5 3 3.5 4

inel. enhanced: Epart > 5 GeV in −5 < η < −3 or 3 < η < 5

1 N dN dη

2
1.5
1
0.5

0.5 1 1.5 2 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 η MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 0.5 1 1.5 2 2.5 3 3.5 4 NSD enhanced: Epart > 5 GeV in −5 < η < −3 and 3 < η < 5

1 N dN dη

2
1.5
1
0.5

0.5 1 1.5 2 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 η MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 0.5 1 1.5 2 SD enhanced: Epart > 5 GeV in either −5 < η < −3 or 3 < η < 5

1 N dN dη

2
1.5
1
0.5

0.5 1 1.5 2 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 η MC/Data

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Measuring on different diffractive event topologies

Will provide further constrains for the models Show where each model does a good/bad description

Integrated pT spectrum

Total 2 —> 2 partonic cross section: Divergent towards low pT

Integrated-pT

—> phenomenological factor [α2

s(p2 T,0 + p2 T)/α2 s(p2 T)][p4 T/(p2 T,0 + p2 T)2]

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)

T min

r(p

4 −

10

3 −

10

2 −

10

1 −

10 1 10

CMS = 8 TeV s pp

| < 6.5 η > 40 MeV) > 0 in 5.3 < |

T

(p

ch

N | < 2.4 η Leading charged particles, |

Data Pythia 6 Z2* Pythia 6 CUET Pythia 6 (default, MPI on) Pythia 6 (default, MPI off) Pythia 6 (default, MPI off, no sat)

[GeV]

T min

p

1 10

MC/Data

0.5 1 1.5

= 9 GeV

T, min

MC scaled to data at p

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Integrated-pT at 8 TeV

arXiv:1507.00233

Integrated pT spectrum

At √s = 8 TeV the turn over happens at pT-min ~ 5GeV

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

How does it look for different diffractive topologies??

Integrated-pT at 8 TeV

)

T min

r(p

4 −

10

3 −

10

2 −

10

1 −

10 1 10

CMS = 8 TeV s pp

| < 6.5 η > 40 MeV) > 0 in 5.3 < |

T

(p

ch

N | < 2.4 η Leading charged particles, |

Data Pythia 8 4C Pythia 8 CUET Pythia 8 MONASH QGSJetII-04 EPOS LHC Herwig++ UE-EE-5C

= 9 GeV

T, min

MC scaled to data at p

[GeV]

T min

p

1 10

MC/Data

0.5 1 1.5

How does it look at different center of mass energies??

Integrated pT spectrum

At √s = 8 TeV the turn over happens at pT-min ~ 5GeV

arXiv:1507.00233

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)

T min

r(p

4 −

10

3 −

10

2 −

10

1 −

10 1 10

CMS = 8 TeV s pp

| < 6.5 η > 40 MeV) > 0 in 5.3 < |

T

(p

ch

N | < 2.4 η Leading charged particles, |

Data Pythia 8 4C Pythia 8 CUET Pythia 8 MONASH QGSJetII-04 EPOS LHC Herwig++ UE-EE-5C

= 9 GeV

T, min

MC scaled to data at p

[GeV]

T min

p

1 10

MC/Data

0.5 1 1.5

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Integrated-pT at 13 TeV. Predictions

√s = 13 TeV

Similar turn over value

P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−5 10−4 10−3 10−2 Selection: inclusive pp r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data

arXiv:1507.00233

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Integrated pT leading distribution. Predictions

For inclusive, inelastic enhanced and NSD samples the turn

ver happens at the same pT-min value

P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−5 10−4 10−3 10−2 Selection: inclusive pp r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−5 10−4 10−3 10−2

inel. enhanced: Epart > 5 GeV in −5 < η < −3 or 3 < η < 5

r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−5 10−4 10−3 10−2 NSD enhanced: Epart > 5 GeV in −5 < η < −3 and 3 < η < 5 r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Integrated pT leading distribution. Predictions

r(pT min)

SD enhanced Sensitive to smaller effective CM energy — Turn over happens at smaller values of pT-min Measuring the as a function of Mx one can a c c e s s t h e e n e r g y dependence of saturation scale

Mx < s

P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−7 10−6 10−5 10−4 10−3 SD enhanced: Epart > 5 GeV in either −5 < η < −3 or 3 < η < 5 r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Integrated pT leading distribution. Predictions

NSD extends to higher pT-min values Turn over shifted to small pT-min

P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−7 10−6 10−5 10−4 10−3 SD enhanced: Epart > 5 GeV in either −5 < η < −3 or 3 < η < 5 r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data P8-CUETP8-heradpdf P8-CUETP8M1 P8-4C P8-Monash EPOS-LHC 10−5 10−4 10−3 10−2 NSD enhanced: Epart > 5 GeV in −5 < η < −3 and 3 < η < 5 r(pT min) 1 10 1 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 pT min [GeV] MC/Data

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Juan Manuel Grados Luyando MPI@LHC Trieste, Italy November 2015

Summary

Pseudorapidity distribution at √s = 13 TeV for inclusive events Predictions for the pseudorapidity density at √s = 13 TeV for different event selections New proposal for extracting information about the energy dependence of the saturation scale Experimental results to be released soon