The Underlying Event in Run II ChgJets versus JetClu Jets

Transcription

1 The Underlying Event in Run II ChgJets versus JetClu Jets Outline of Talk! The evolution of charged particle jets and the underlying event. Study the event topology relative to the leading chgjet and compare with Run I.! The evolution of calorimeter jets and the underlying event. Study the event topology relative to the leading JetClu jet. Charged Particle Jet Calorimeter Jet! Charged particle jets versus calorimeter jets. Study the relationship between chgjets and JetClu jets. Rick Field Page 1

2 The Underlying Event in Run II ChgJets versus JetClu Jets Outline of Talk! The evolution of charged particle jets and the underlying event. Study the event topology relative to the leading chgjet and compare with Run I.! The evolution of calorimeter jets and the underlying event. Study the event topology relative to the leading JetClu jet.! Charged particle jets versus calorimeter jets. Study the relationship between chgjets and JetClu jets. Look at the charged particle correlation relative to the leading chgjet. Charged Particle Jet Look at the charged particle correlation relative to the leading calorimeter jet. Look correlation between the leading chgjet and calorimeter jets. Calorimeter Jet Rick Field Page 2

3 Data Selection Anwar's New Stntuples JET20 JET50 JET70 JET100 Event Selection Good Runs Bad Stntuples Removed MetSig < 5 sumet < 2 TeV One and only one Z-vertex z 0 < 60 cm Total Events Good Events (Rob's WEB) Met Cut (MetSig < 5, sumet < 2 TeV) 1 ZVTX z < 60 cm JetClu ( η(jet) < 2, R = 0.7) 7,388,639 5,185,515 5,177,984 3,038,879 2,422,404 1,844,407 1,397,771 1,370, , , , , , , ,238 1,052, , , , ,991 Same as our Run 1 analysis! Track Selection COT measured tracks z-z 0 < 2 cm d 0 < 1 cm P T > 0.5 GeV/c η < 1 JetClu ( η(jet) < 0.7, R = 0.7) ChgJet (P T > 0.5 GeV, η < 2, R = 0.7) Form charged particle jets (R = 0.7) as we did our Run 1 analysis 1,118,787 3,018, , , , ,135 Calorimeter Jet Selection JetClu (R = 0.7) η(jet) < 2 or η(jet) < , ,276 Rick Field Page 3

4 PYTHIA Tune A Charles Currat s Stntuples (PYTHIA Tune A at 1.96 TeV) Number of Events 1,000, ,000 10,000 1, Number of Events PThard (GeV/c) PThat > 90 GeV PThat > 60 GeV PThat > 40 GeV PThat > 18 GeV PThat > 10 GeV PThat > 5 GeV PThat > 0 GeV PT(min) Total N(events) 500, , , , , , ,900 3,363,400 dσ/dpthard (µb/gev) 1.0E E E E E E E E E E E-06 Can only go out to PT(hard) of about 250 GeV/c. Generated 2-to-2 Hard Scattering PT(hard) PT(hard) (GeV/c) PThat > 0 GeV PThat > 5 GeV PThat > 10 GeV PThat > 18 GeV PThat > 40 GeV PThat > 60 GeV PThat > 90 GeV! Form weighted histograms using P T (hard) so that I can use all 3,363,400 generated events! Need another run with PT(min) = 125 GeV/c! Rick Field Page 4

5 Cross-Sections Leading ChgJet Cross Section Leading Jet Cross Section 1.0E E E E E+00 dσ/dpt (µb/gev) 1.0E E E E-04 PY Tune A CDF Run2 dσ/det (µb/gev) 1.0E E E E-04 PY Tune A CDF Run2 1.0E E TeV η <1.0 PT>0.5 GeV R = E-06 JetClu R = 0.7 η(jet) < 2 1.0E PT(charged jet#1) (GeV/c) 1.0E ET(jet#1) (GeV)! Normalize PYTHIA Tune A to fit the leading chgjet cross-section predict the leading JetClu jet cross-section! Rick Field Page 5

6 Evolution of Charged Jets! Shows the data on the average number of charged particles within the leading charged particle jet ( η <1, P T >0.5 GeV, R = 0.7) as a function of the transverse momentum of the leading charged particle jet from Run 1. Averave Nchg Nchg(chgjet#1) versus PT(chgjet#1) CDF Run 1 Data 1.8 TeV η <1.0 PT>0.5 GeV R = PT(charged jet#1) (GeV/c) CDF Run 1 Min-Bias CDF Run 1 JET20 Rick Field Page 6

7 Evolution of Charged Jets PYTHIA produces too many charged particles in the leading chgjet! 12 Nchg(chgjet#1) versus PT(chgjet#1)! Shows the data on the average number of charged particles within the leading charged particle jet ( η <1, P T >0.5 GeV, R = 0.7) as a function of the transverse momentum of the leading charged particle jet from Run 1. Excellent agreement between Run 1 and 2! Averave Nchg PT(charged jet#1) (GeV/c) PY Tune A CDF Run 2 CDF Run 1 Min-Bias CDF Run 1 JET20 η <1.0 PT>0.5 GeV R = 0.7! Compares the Run 2 data (JET20, JET50, JET70, JET100) with Run 1. Rick Field Page 7

8 Run 2 COT Efficiency COT Charged Particle "Efficiency" COT Charged Particle "Efficiency" Observed/Generated All PT "Good" Tracks PT > 0.5 GeV/c Observed/Generated "Good" Tracks η < Pseudorapidity η PT(charged) (GeV/c)! Shows the Run 2 COT efficiency versus η for good tracks with P T > 0.5 GeV/c and all P T. The efficiency is the ratio of the observed good tracks (after CDFSIM) to the generated charged particles.! Shows the Run 2 COT efficiency versus P T for good tracks with η < 1.! In Run 1 we assumed a COT efficiency of 92% for P T > 0.5 GeV/c and η < 1. Rick Field Page 8

9 Evolution of Charged Jets Charged Jet #1 region Direction is very sensitive to the underlying event! Toward-Side Toward-side Jet jet (always) φ Toward Underlying Event Charged Particle φ Correlations P T > 0.5 GeV/c η < 1 Charged Jet #1 Direction φ Toward φ 2π Away Region Transverse Region Leading ChgJet Toward Region Look at the charged particle density in the transverse region! Away Away Transverse Region Away-side jet Away-Side Jet Perpendicular to the plane of the 2-to-2 hard scattering Away Region 0-1 η +1 (sometimes)! Look at charged particle correlations in the azimuthal angle φ relative to the leading charged particle jet.! Define φ φ < 60 o as Toward, 60 o < φ φ < 120 o as, and φ φ > 120 o as Away.! All three regions have the same size in η-φ space, ηx φ φ = 2x120 o = 4π/3. Rick Field Page 9

10 CDF Min-Bias Data Charged Particle Density Charged Particle Pseudo-Rapidity Distribution: dn/dη Charged Particle Density: dn/dηdφ 7 6 CDF Published CDF Published dn/dη CDF Min-Bias 1.8 TeV CDF Min-Bias 630 GeV all PT Pseudo-Rapidity η dn/dηdφ CDF Min-Bias 630 GeV CDF Min-Bias 1.8 TeV all PT Pseudo-Rapidity η <dn! chg Shows /dη> = 4.2 CDF Min-Bias data on the number <dn chg /dηdφ> of charged = 0.67 particles per unit pseudo-rapidity at 630 and 1,800 GeV. There are about 4.2 charged particles per unit η in Min-Bias collisions at 1.8 TeV ( η < 1, all P T ).! Convert to charged particle density, dn chg /dηdφ, by dividing by 2π. ηx φ φ = 1 There are about 0.67 charged particles per unit η-φ in Min-Bias φ = 1 collisions at 1.8 TeV ( η < 1, all P T ) η = 1 Rick Field Page 10

11 CDF Min-Bias Data Charged Particle Density Charged Particle Pseudo-Rapidity Distribution: dn/dη Charged Particle Density: dn/dηdφ 7 6 CDF Published CDF Published dn/dη CDF Min-Bias 1.8 TeV CDF Min-Bias 630 GeV all PT Pseudo-Rapidity η dn/dηdφ CDF Min-Bias 630 GeV CDF Min-Bias 1.8 TeV all PT Pseudo-Rapidity η <dn! chg Shows /dη> = 4.2 CDF Min-Bias data on the number <dn chg /dηdφ> of charged = 0.67 particles per unit pseudo-rapidity at 630 and 1,800 GeV. There are about 4.2 charged particles per unit η in Min-Bias collisions at 1.8 TeV ( η < 1, all P T ).! Convert to charged particle density, dn chg /dηdφ, by dividing by 2π. ηx φ φ = 1 There are about 0.67 charged particles per unit η-φ in Min-Bias φ = 1 collisions at 1.8 TeV ( η < 1, all P T ) ! There are about 0.25 charged particles per unit η-φ in Min-Bias collisions at 1.8 TeV ( η < 1, P T > 0.5 GeV/c). η = 1 Rick Field Page 11

12 Charged Particle Density Charged Jet #1 Direction φ Toward Away CDF Min-Bias data ( η <1, P T >0.5 GeV) <dn chg /dηdφ> = 0.25 "Transverse" Charged Density "Transverse" Charged Particle Density: dn/dηdφ CDF Run 1 Data PT(charged jet#1) (GeV/c) CDF Run 1 Min-Bias CDF Run 1 JET TeV η <1.0 PT>0.5 GeV! Shows the data on the average transverse charge particle density ( η <1, P T >0.5 GeV) as a function of the transverse momentum of the leading charged particle jet from Run 1. Rick Field Page 12

13 Charged Particle Density Charged Jet #1 Direction φ Toward Away Excellent agreement between Run 1 and 2! "Transverse" Charged Density "Transverse" Charged Particle Density: dn/dηdφ PT(charged jet#1) (GeV/c) PY Tune A CDF Run 2 CDF Run 1 Min-Bias CDF Run 1 JET20 η <1.0 PT>0.5 GeV PYTHIA Tune A was tuned to fit the underlying event in Run I!! Shows the data on the average transverse charge particle density ( η <1, P T >0.5 GeV) as a function of the transverse momentum of the leading charged particle jet from Run 1.! Compares the Run 2 data (JET20, JET50, JET70, JET100) with Run 1. Rick Field Page 13

14 Charged PTsum Density Charged Jet #1 Direction φ Toward Away "Transverse" PTsum Density (GeV) "Transverse" Charged PTsum Density: dptsum/dηdφ CDF Run 1 Data CDF JET20 CDF Min-Bias 1.8 TeV η <1.0 PT>0.5 GeV PT(charged jet#1) (GeV/c)! Shows the data on the average transverse charged PTsum density ( η <1, P T >0.5 GeV) as a function of the transverse momentum of the leading charged particle jet from Run 1. Rick Field Page 14

15 Charged Jet #1 Direction φ Toward Away Charged PTsum Density Excellent agreement between Run 1 and 2! "Transverse" PTsum Density (GeV) "Transverse" Charged PTsum Density: dptsum/dηdφ CDF Run Preliminary 1 Data data CDF JET20 CDF Min-Bias 1.8 TeV η <1.0 PT>0.5 η <1.0 η <1.0 GeV PT>0.5 PT>0.5 GeV GeV PT(charged jet#1) (GeV/c) PY Tune A CDF Run 2 CDF CDF JET20 JET20 CDF CDF Min-Bias Min-Bias PYTHIA Tune A was tuned to fit the underlying event in Run I!! Shows the data on the average transverse charged PTsum density ( η <1, P T >0.5 GeV) as a function of the transverse momentum of the leading charged particle jet from Run 1.! Compares the Run 2 data (JET20, JET50, JET70, JET100) with Run 1. Rick Field Page 15

16 Relationship Between JetClu Jets and ChgJets Average ET (GeV) PY Tune A CDF Run 2 ET(jet#1) vs PT(charged jet#1) PT(charged jet#1) (GeV/c) JetClu (R = 0.7, η(jet#1) < 2) Charged Particles ( η <1.0, PT>0.5 GeV/c) Average Fraction PT(chgjet#1)/ET(closest jet) vs PT(chgjet#1) PT(charged jet#1) (GeV/c) PY Tune A CDF Run 2 JetClu (R = 0.7, η(jet#1) < 2) Charged Particles ( η <1.0, PT>0.5 GeV/c)! Shows the leading JetClu jet ET versus the transverse momentum of the leading charged particle jet.! Shows the ratio of P T (chgjet#1) to the closest JetClu jet ET versus P T (chgjet#1).! Shows the EM fraction of the closest JetClu jet versus P T (chgjet#1) together with the EM fraction of a typical JetClu jet. Average Fraction Jet closest to ChgJet#1 JetClu EM Fraction Leading Jet η(jet) < PT(chgjet#1) or ET(jet#1) (GeV) JetClu R = 0.7 Rick Field Page 16

17 Relationship Between JetClu Jets and ChgJets Average Fraction PT(chgjet#1)/ET(closest jet) vs PT(chgjet#1) PT(charged jet#1) (GeV/c) PY Tune A CDF Run 2 JetClu (R = 0.7, η(jet#1) < 2) Charged Particles ( η <1.0, PT>0.5 GeV/c) dσ/dpt (µb/gev) 1.0E E E E E E-04 Leading Jet & ChgJet Cross-Sections JetClu Jet#1 R = 0.7 η(jet) <0.7! Shows the ratio of P T (chgjet#1) to the closest JetClu jet E T versus P T (chgjet#1). 1.0E E-06 ChgJet#1 R = 0.7! Shows relative cross-sections for producing a leading chgjet with transverse momentum P T (chgjet#1) ( η < 1) and for producing a leading JetClu jet ( η < 0.7) with transverse energy E T (jet#1). 1.0E-07 At E T (jet#1) = 125 GeV about 1 in 10 JetClu jets are composed of > 90% charged particles! (maybe?) PT(chgjet#1) or ET(jet#1) (GeV) Rick Field Page 17

18 JetClu Jet #1 Direction region is very sensitive to the underlying event! Toward Evolution of JetClu Jets Underlying Event Toward-Side Jet φ Charged Particle φ Correlations P T > 0.5 GeV/c η < 1 JetClu Jet #1 Direction Toward φ φ 2π Away Region Transverse Region Toward Region Leading Jet Look at the charged particle density in the transverse region! Away Away Transverse Region Away-side jet Away-Side Jet Perpendicular to the plane of the 2-to-2 hard scattering Away Region 0-1 η +1 (sometimes)! Look at charged particle correlations in the azimuthal angle φ relative to the leading JetClu jet.! Define φ φ < 60 o as Toward, 60 o < φ φ < 120 o as, and φ φ > 120 o as Away.! All three regions have the same size in η-φ space, ηx φ φ = 2x120 o = 4π/3. Rick Field Page 18

19 JetClu Charged Particle Density JetClu Jet #1 Direction φ Toward Away "Transverse" Charged Density "Transverse" Charged Particle Density: dn/dηdφ ET(jet#1) (GeV) PY Tune A CDF Run 2 JetClu (R = 0.7, η(jet#1) < 2) Charged Particles ( η <1.0, PT>0.5 GeV/c)! Shows the data on the average transverse charge particle density ( η <1, PT>0.5 GeV) as a function of the transverse energy of the leading JetClu jet (R = 0.7, η(jet) < 2) from Run 2 compared with the predictions of PYTHIA Tune A. Rick Field Page 19

20 JetClu Charged Particle Density JetClu Jet #1 or Direction ChgJet#1 Direction φ φ Toward Toward Away Away "Transverse" Charged Density "Transverse" Charged Particle Density: dn/dηdφ ChgJet#1 R = 0.7 JetClu Jet#1 (R = 0.7, η(jet) <2) Charged Particles ( η <1.0, PT>0.5 GeV/c) PT(chgjet#1) or ET(jet#1) (GeV)! Shows the data on the average transverse charge particle density ( η <1, PT>0.5 GeV) as a function of the transverse energy of the leading JetClu jet (R = 0.7, η(jet) < 2) from Run 2 compared with the predictions of PYTHIA Tune A.! Compares the transverse region of the leading chgjet with the transverse region of the leading JetClu jet. Rick Field Page 20

21 JetClu Charged PTsum Density JetClu Jet #1 Direction φ Toward Away "Transverse" PTsum Density (GeV) "Transverse" Charged PTsum Density: dptsum/dηdφ PY Tune A Fit CDF Run ET(jet#1) (GeV) JetClu (R = 0.7, η(jet#1) < 2) Charged Particles ( η <1.0, PT>0.5 GeV/c)! Shows the data on the average transverse charged PTsum density ( η <1, PT>0.5 GeV) as a function of the transverse energy of the leading JetClu jet (R = 0.7, η(jet) < 2) from Run 2 compared with the predictions of PYTHIA Tune A. Rick Field Page 21

22 JetClu Charged PTsum Density JetClu Jet #1 JetClu Jet #1 or ChgJet#1 Direction Direction φ φ Toward Toward Away Away "Transverse" PTsum Density (GeV) "Transverse" Charged PTsum Density: dptsum/dηdφ ChgJet#1 R = 0.7 JetClu Jet#1 (R = 0.7, η(jet) <2) Charged Particles ( η <1.0, PT>0.5 GeV/c) PT(chgjet#1) or ET(jet#1) (GeV)! Shows the data on the average transverse charged PTsum density ( η <1, PT>0.5 GeV) as a function of the transverse energy of the leading JetClu jet (R = 0.7, η(jet) < 2) from Run 2 compared with the predictions of PYTHIA Tune A.! Compares the transverse region of the leading chgjet with the transverse region of the leading JetClu jet. Rick Field Page 22

23 Structure of the Leading ChgJet and JetClu Jet Nchg(jet#1) and Nchg(charged jet#1) EM & Seed Fraction Jet#1 vs ET(jet#1) EM Fraction Seed Fraction Averave Nchg Nchg(chgjet#1) Nchg(jet#1) Charged Particles ( η <1.0, PT>0.5 GeV/c) JetClu R = 0.7 η(jet) < ET(jet#1) or PT(charged jet#1) (GeV) Average Fraction JetClu R = 0.7 η(jet) < 0.7 Generated Neutral PTsum Fraction ET(jet#1) (GeV)! Shows the average number of charged particles within the leading JetClu jet and within the leading chgjet.! Shows the EM fraction and the Seed fraction of the leading JetClu jet.! Shows the fraction of charged PTsum and the charged PTmax fraction within the leading JetClu jet. Average Charged Fraction PTsum/ET(Jet#1) and PTmax/ET(jet#1) PTmax(chg)/ET(jet#1) PTsum(chg)/ET(jet#1) Charged Particles ( η <1.0, PT>0.5 GeV/c) ET(jet#1) (GeV) JetClu R = 0.7 η(jet) < 0.7 Rick Field Page 23

24 Global Charged Multiplicity Global N(charged) Global Nchg vs ET(jet#1) Average Nchg 20 JetClu R = 0.7 η(jet) < 2 Average Nchg 20 η(jet) < 2 15 ChgJet#1 Charged Particles ( η <1.0, PT>0.5 GeV/c) PT(chgjet#1) or ET(jet#1) (GeV) 15 η(jet) < 0.7 JetClu R = 0.7 Charged Particles ( η <1.0, PT>0.5 GeV/c) ET(jet#1) (GeV)! Shows the overall average number of charged particles (P T > 0.5 GeV/c, η < 1) as a function of the leading JetClu jet ET and as function of the transverse momentum of the leading chgjet.! Shows the overall average number of charged particles (P T > 0.5 GeV/c, η < 1) as a function of the leading JetClu jet ET for η(jet#1) < 2 and η(jet#1) < 0.7. Rick Field Page 24

25 Global Charged PTsum Average PTsum (GeV) ChgJet#1 Global Charged PTsum PT(chgjet#1) or ET(jet#1) (GeV) JetClu R = 0.7 η(jet) < 2 Charged Particles ( η <1.0, PT>0.5 GeV/c) Average PTsum (GeV) Global Charged PTsum vs ET(jet#1) JetClu R = 0.7 η(jet) < ET(jet#1) (GeV) η(jet) < 2 Charged Particles ( η <1.0, PT>0.5 GeV/c)! Shows the overall average charged PTsum (PT > 0.5 GeV/c, η < 1) as a function of the leading JetClu jet ET and as function of the transverse momentum of the leading chgjet.! Shows the overall average charged PTsum (PT > 0.5 GeV/c, η < 1) as a function of the leading JetClu jet ET for η(jet#1) < 2 and η(jet#1) < 0.7. Rick Field Page 25

26 Summary Outgoing Parton Proton Underlying Event PT(hard) Initial-State Radiation AntiProton Underlying Event The Underlying Event in Run 2 Outgoing Parton Final-State Radiation Same conclusion as Mario!! There is excellent agreement between Run 1 and Run 2 for charged particles. The underlying event is the same in Run 2 as in Run 1 but now I can study the evolution out to much higher energies!! PYTHIA Tune A does a good job of describing the underlying event in the Run 2 data for both charged particle jets and calorimeter jets. However, I still need to study the distributions in the transverse region.! I need Min-Bias Stntuples so I can follow the evolution of charged particle jets (and calorimeter jets) to lower energies. (I will learn how to make Stntuples!)! Lots more to come including MAX/MIN transverse and MAX/MIN cones and transverse P T distributions. Rick Field Page 26

27 Summary Outgoing Parton Proton Underlying Event PT(hard) Initial-State Radiation AntiProton Underlying Event The Overall Event in Run 2 Outgoing Parton Final-State Radiation PYTHIA Tune A does not fit everything!! PYTHIA Tune A (CTEQ5L) does not agree with the shape of the calorimeter jet crosssection and it predicts a larger charged particle fraction (i.e. larger charged PTsum) within the leading calorimeter jet than in the Run 2 data. I still need to study the distributions!! PYTHIA Tune A produces too many charged particles within the leading calorimeter jet and within the leading chgjet. (I tuned the underlying event not the jet fragmentation!).! Much more to come, but we need another PYTHIA Tune A run with PT(min) = 125 GeV/c so we can compare at high ET. Rick Field Page 27

28 Summary Outgoing Parton Proton Underlying Event PT(hard) Initial-State Radiation AntiProton Underlying Event The Overall Event in Run 2 Outgoing Parton Final-State Radiation In this talk I have presented mostly average quantities. Now I must study the! PYTHIA Tune A (CTEQ5L) does distributions not agree from with which the shape of the calorimeter jet crosssection and it predicts a larger charged particle fraction (i.e. larger charged PTsum) these averages came. within the leading calorimeter jet than in the Run 2 data. I still need to study the distributions!! PYTHIA Tune A produces too many charged particles within the leading calorimeter jet and within the leading chgjet. (I tuned the underlying event not the jet fragmentation!).! Much more to come, but we need another PYTHIA Tune A run with P T (min) = 125 GeV/c so we can compare at high ET. Rick Field Page 28