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Charge conservation effect in first longitudinal coefficient a_{1} as a function of <dNch/deta> in Pb-Pb collisions

Figure Information
Scope: PWG
PWG-CF (Flow and Correlations)
Energy
5.02 TeV
System
Pb-Pb
Figure Group
Longitudinal Fluctuations in Heavy-Ion Collisions with the ALICE Detector
Figure Image
Figure image (.eps)
final_pb_posneg_0.eps
Figure image (.pdf)
final_pb_posneg_0.pdf
Figure Caption

The first longitudinal coefficient a1 as a function of <dNch/deta> in Pb-Pb collisions at √sNN = 5.02 TeV, compared between data and MC HIJING. Charge conservation effect in charged, and positive and negative only tracks. Statistical and systematic uncertainties are included.

Detail description

The first longitudinal coefficient a1 as a function of <dNch/deta> in Pb-Pb collisions at √sNN = 5.02 TeV(LHC18r, LHC18q) compared between data and MC HIJING. a1 was computed EbyE using Legendre polynomial decomposition. For Pb-Pb data, both periods with different polarities LHC18q and LHC18r were analyzed and merged. The values used for <dNch/deta> are published values from ALICE (arXiv:1512.06104). Statistical and systematic uncertainties are included. Systematic errors are averaged along centrality.

Event acceptance:

  • 0.2<pT<2.0 GeV/c
  • -0.8<eta<0.8
  • -8<Vz<8 cm
  • FilterBit: 768
  • TPC Ncls > 70
  • TPC N crossed rows >70
  • number of eta bins: 16
  • Pb-Pb chi2/NDF<2.5
  • Pileup cuts applied for Pb-Pb using DPG cuts (https://indico.cern.ch/event/957574/contributions/4094213/att achments/2141330/3608130/DPG_AliceWeek_20201111.pdf)
  • Charged/postive/negative tracks only

Systematic checks:

  • chi2/NDF<2.3 (Pb-Pb)
  • chi2/NDF<2 (Pb-Pb)
  • No cut/looser/even more looser/very loose pileup cut (Pb-Pb)
  • TPC N crossed rows >100
  • TPC Ncls >80
  • -7<Vz<7cm
  • -6<Vz<6cm
  • -8<Vz<-0.2 && 0.2<Vz<8 cm
  • FilterBit: 96
  • number of eta bins: 32