Ilya Selyuzhenkov February 06, 2009

Data sets

• pp2006 - STAR 2006 pp longitudinal data (~ 3.164 pb^1)
  Trigger: eemc-http-mb-L2gamma [id:137641]
• mc2006: gamma-jet+QCD jets [p6410EemcGammaFilter] events.

Partonic pt range 2-25 GeV.

• pp2008 - STAR 2008 pp data
  Trigger: etot-mb-l2 [id:7]

Cuts applied

• Di-jet events
• Require to reconstruct photon momentum (no gamma-jet isolation cuts)
• Gamma pt > 7GeV, jet pt > 7GeV
• L2gamma emulation in Monte-Carlo
• L2gamma triggered for pp2006 and pp2008 events
• cos (phi_jet - phi_gamma) < -0.8
• detector |eta_jet|< 0.8
• |v_z| < 100

Figures

Each figure has:

• All pre-shower conditions combined, No pre-shower cuts
• Red circles show pp2006 data
• Black triangles show pp2008 data
  Data scaled to match the integraled yield from pp2006 data
• Green line shows MC sum: QCD + gamma-jet
  Monte-Carlo results for QCD and gamma-jet samples are first
  scaled to 3.164 pb^-1 according to Pythia luminosity,
  added together, and then an additional fudge factor of 1.24 applied.
  Fudge factor is defined as pp2006 to Monte-Carlo sum ratio
  for pt_jet>7GeV and pt_gamma>7 candidates

Kinematics

Figure 1: vertex z

Figure 2: photon detector eta

Figure 3: jet detector eta

Figure 4: photon pt

Figure 5: jet pt

Figure 6: gamma-jet pt balance

Figure 7: Photon neutral energy fraction

Figure 8: Jet neutral energy fraction

Figure 9: cos(phi_gamma-phi_jet)

Photon candidate's 2x1, 2x2, and 3x3 tower cluser energy

Figure 10: 3x3 cluster energy

Figure 11: 2x1 cluster energy

Figure 12: 2x2 cluster energy

Number of charge tracks, Barrel and Endcap towers within r=0.7 for photon and gamma

Figure 13: Number of charged track associated with photon candidate

Figure 14: Number of Barrel towers associated with photon candidate

Figure 15: Number of Endcap towers associated with photon candidate

Jet energy composition

Figure 16: Jet energy part from Barrel towers

Figure 17: Jet energy part from charge tracks