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Updates on the study of dihadron correlation

Updates on the study of dihadron correlation. Liang Zheng EIC task force meeting . What we have done up to now and where are we going?. We have made the plots benchmarking possible underlying physics channel through the measurements of dihadron correlation.

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Updates on the study of dihadron correlation

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  1. Updates on the study of dihadron correlation Liang Zheng EIC task force meeting

  2. What we have done up to now and where are we going? We have made the plots benchmarking possible underlying physics channel through the measurements of dihadron correlation. We come up with a comparison between our Monte Carlo results and a theoretical prediction with saturation. Possible detector effect is studied by a fast smearing method. Performance of measurements with different luminosities. Webpage as a memo note for the work has been updated in our wikipage: https://wiki.bnl.gov/eic/index.php/Dihadron

  3. Part One: Benchmark plots for ep ∆φ distribution for All process No realistic luminosity issue considered. e+p20x100GeV, PYTHIA default setting 1<Q2<1.5, 0.65<y<0.75, <x>=2.2e-4 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig

  4. Part One: Benchmark plots for ep ∆φ distribution for DIS process e+p20x100GeV, PYTHIA default setting 1<Q2<1.5, 0.65<y<0.75, <x>=2.2e-4 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig PGF process 61.06% QCDC process 10.51%

  5. Part One: Benchmark plots for ep ∆φ distribution for Resolved process q+q channel 8.59% e+p20x100GeV, PYTHIA default setting 1<Q2<1.5, 0.65<y<0.75, <x>=2.2e-4 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig q+g channel 17.82% g+g channel 1.76%

  6. Part One: Benchmark plots for ep Fraction of different processes out of total versus ∆φ e+p20x100GeV, PYTHIA default setting 1<Q2<1.5, 0.65<y<0.75, <x>=2.2e-4 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig

  7. Part One: Benchmark plots for ep ∆φ distribution and QCD radiation 1. Intrinsic kT 2. Initial state Parton Shower 3. Final state Parton Shower 4. Fragmentation pT 5. Particle decay dominate e+p20x100GeV 1<Q2<1.5, 0.65<y<0.75 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig Away side Near side With particle decay contribution Without particle decay contribution

  8. Part One: Benchmark plots for eA eA with nuclear PDF vsep (all process included) Relevant nuclear effects: 1. Nuclear PDF 2. Energy loss e+p/Au 20x100GeV, PYTHIA default setting 1<Q2<1.5, 0.65<y<0.75 charged hadrons, 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig eAu Energy loss vs nuclear PDF eAuvsep

  9. Part Two: Compare with CGC ep∆φ at different kTwith JETSET fragmentation kT = 0.4 e+p30x100GeV 0.5<Q2<1.5, 0.65<y<0.75 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig Parton shower switched off, blue curve from Bowen’s calculation without fragmentation pT kT = 0.6 kT = 0.7

  10. Part Two: Compare with CGC ep∆φwith JETSET fragmentation when fragpT on kT distribution changed from PYTHIA default: e+p30x100GeV 0.5<Q2<1.5, 0.65<y<0.75 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig to a gauss distribution with σ=0.6 Parton shower switched off, blue/green curve from Bowen’s calculation w/o or with fragmentation pT No decay result rescaled based on the decay integral FragpT = 0.3 FragpT = 0.4

  11. Part Two: Compare with CGC ep∆φwith DSS fragmentation kT from a gauss distribution function e+p30x100GeV 1.0<Q2<2.0, 0.65<y<0.75 0.25 < z trig, z asso < 0.35 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig with σ=0.6 Factorization scale: Parton shower switched off, blue/green curve from Bowen’s calculation w/o or with fragmentation pT No fragpT fragpT= 0.4

  12. Part Two: Compare with CGC ep∆φwith DSS fragmentation kT from a gauss distribution function e+p30x100GeV 3.5<Q2<4.5, 0.65<y<0.75 0.25 < z trig, z asso < 0.35 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig with σ=0.6 Factorization scale: Parton shower switched off, blue/green curve from Bowen’s calculation w/o or with fragmentation pT No fragpT fragpT= 0.4

  13. Part Three: Detector smearing Smearing detector layout Central tracker -1< η < 1, point resolution 80 microns, 45 fit points Forward/backward tracker 1< η < 3.5, -3.5 < η < -1, point resolution 80 microns, 6 planes Far forward/backward tracker 3.5 < η < 4.5, -4.5 < η < -3.5, point resolution 20 microns, 12 planes Central: radial tracker Forward/Backward: planar tracker Magnetic Field: B=0.3T Radiation length: 0.03 Simply tracking resolution considered.

  14. Part Three: Detector smearing Kinematics migration Unsmeared scattered electron direction Electrons in forward/backward tracking region Unsmeared event sample with cuts: 0.5 < y < 0.9, 2 < Q2 < 6 20x100 GeV Q2vs x unsmeared 20x100 GeV Q2vs x smeared

  15. Part Three: Detector smearing Kinematics migration Smearing loss mainly come from kinematics migration. Tracking information for electron not good enough in such a region… Smeared variable cut:2.5<Q2<5, 0.55<y<0.8 out from the event sample with unsmeared kinematics: 2<Q2<6, 0.5<y<0.9 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig Tracking worse for higher electron momentum 30x100 GeV smeared loss due to kinematics migration 20x100 GeV smeared loss due to kinematics migration

  16. Part Three: Detector smearing detector smearing effect No kinematics migration. (No smeared Q2/y cuts) e+p30x100GeV 2<Q2<6, 0.5<y<0.9 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig Hadron pairs in center and forward/backward tracking region!

  17. Part Three: Detector smearing Two particle correlation with smearing No kinematics migration. (No smeared Q2/y cuts) e+p30x100GeV 2<Q2<6, 0.5<y<0.9 0.2 < z trig, z asso < 0.4 pTtrig > 2 GeV, 1 GeV < pTasso < pTtrig If no Q2/x migration, no strong smearing effect. Trig pT smearing Associate pT smearing

  18. Part Four: Double gauss fit Underlying quark pT imbalance probed by correlation “pT imbalance” means the vector sum of the transverse momentum of two outgoing quarks ep 20x100 0.65<y<0.75, 0.5<Q2<1.5 pTtrig >2, 1 < pTasso < pTtrig 0.2<z<0.4 Charged particle, all effects/ no Initial radiation

  19. Part Four: Double gauss fit ∆φ at different kTstudied by double gauss fit ep 20x100 0.65<y<0.75, 1<Q2<1.5 pTtrig >2, 1 < pTasso < pTtrig 0.2<z<0.4 Charged particle all effects on Fit parameters

  20. Part Five: Kinematics scan Kinematics region in Q2 and x we will approach Kinematics span for ep 30/20/10 x100 GeV event samples in the bin of y in [0.6, 0.8] , [0.25, 0.35]; and Q2 in [0.5, 1.5], [3, 5], [9, 11], [15.5, 20.5]. Black : 30x100 Red : 20x100 Green:10x100

  21. Part Five: Kinematics scan ∆φ for ep and eAu with 10 fb-1 ep (dots)/ eAu(open triangle) 20x100 Lumi=10 fb-1 ep/eAu20x100 GeV pTtrig >2, 1 < pTasso < pTtrig, 0.2<z<0.4 Charged particle all effects on y increasing Q2 increasing Black:all Red:PGF

  22. Part Five: Kinematics scan JeAuvsxAfrag with 10 fb-1 ep (dots)/ eAu(open triangle) 20x100 Lumi=10 fb-1 ep/eAu20x100 GeV pTtrig >2, 1 < pTasso < pTtrig, 0.2<z<0.4 Charged particle all effects on y increasing [Npair(xAfrag)/Nevt]eAu JeA= [Npair(xAfrag)/Nevt]ep Q2 increasing Black:all Red:PGF

  23. Part Five: Kinematics scan JeAuvsxg with 10 fb-1 ep (dots)/ eAu(open triangle) 20x100 Lumi=10 fb-1 ep/eAu20x100 GeV pTtrig >2, 1 < pTasso < pTtrig, 0.2<z<0.4 Charged particle all effects on y increasing [Npair(xg)/Nevt(xg)]eAu JeA= [Npair(xg)/Nevt(xg)]ep Q2 increasing Black:all Red:PGF If analyzed in every xg bin, Pair dependence on xg will be canceled by event dependence.

  24. Part Five: Kinematics scan Fitted width from double gauss for ep/eAu

  25. Part Five: Kinematics scan ∆φ for ep and eAu with 1 fb-1 ep (dots)/ eAu(open triangle) 20x100 Lumi=10 fb-1 ep/eAu20x100 GeV pTtrig >2, 1 < pTasso < pTtrig, 0.2<z<0.4 Charged particle all effects on y increasing Q2 increasing Black:all Red:PGF

  26. Part Five: Kinematics scan Fitted width from double gauss for ep/eAu with 1 fb-1

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