Pi0 raw and production spectra in EMCAL

Reconstruction efficiency

The reconstructed efficiency was defined as the ratio of the reconstructed raw pi0 spectrum to the generated one and normalized for the unit of rapidity, and full azimuth angle.

Statistics

6.3 Mevents, pi0 pt range 0-30 GeV/c

Conditions of generation

  1. MC with single pi0 per event with unform distribution over transverse momentum, azimuth angle and polar angle was simulated.
  2. Full simulation with real ALICE geometry.
  3. The generation angle was chosen larger than EMCAL acceptance to avoid aperture effects.
  4. Real bad channel map was used.
  5. Non-linearity correction was calculated on this dataset and applied.

Cluster selection

  1. Number of cells in cluster: no cut.
  2. Cluster pt threshold: 0.5 GeV/c
  3. Clusters with the leading cell closer that 1 cell to the SM edge and to warm cells were removed.

MC non-linearity correction

Non-linearity correction was calculated on the MC data, parametrized by the function (see fig. below left) and applied. The result of the correction is demonstrated on the fig. below right.

MCnonlincorr.png MCafterNonlin.png

Efficiency function

Efficiency_all.png

The red and blue curves denote parametrization of the efficiency fit by two functions:

Without the unfolding:

  • Red: eff(pt) = 0.035*(1-3.37*exp(-1.105 pt + 0.1105 pt))
  • Blue: eff(pt) = 0.02749*(exp(0.1697 pt) - 5.185 + 17.44/pt)
  • Junction point: pt=5.5-6.1, the function value is frozen in this region

The junction point denotes the transition phase - new physical effect (cluster merging) start to dominate.

Raw pi0 spectrum

Statistics

For the analysis 200 Mevents LHC10e pass1 with AliPhysicsSelection were used.

Cluster selection

  1. No misalignment applied (to make the same conditions as in MC simulation)
  2. For calibration only cluster position recalculation with logarithmic weight 4.82 was applied
  3. Non-linearity correction applied (currently used the old "plateau" correction, the same as https://twiki.cern.ch/twiki/bin/view/ALICE/EMCALnonlinCorr)
  4. Number of cells in cluster: no cuts
  5. Cluster pt threshold: 0.5 GeV/c
  6. Clusters with the leading cell closer that 1 cell to the SM edge and to warm cells were removed.

without unfolding

pi0raw.png

with the unfolding

PHOSvsTPC-2010-Nov-06.png

   

Pi0 production stectrum

Production yeild of pi0 mesons in pp collisions 7 TeV in EMCAL vs PHOS and conversion groups.

Now we are 50% off their results and we have the strating point to move on.

prod_all.png

Cluster selection

  1. Misalignment from Rongrong applied
  2. Pi0 calibration coefficients applied
  3. Non-linearity correction applied (currently used the old "plateau" correction, the same as https://twiki.cern.ch/twiki/bin/view/ALICE/EMCALnonlinCorr)
  4. Number of cells in cluster: no cuts
  5. Cluster pt threshold: 0.5 GeV
  6. Clusters with the leading cell closer that 1 cell to the SM edge and to warm cells were removed.
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Topic revision: r5 - 2010-11-08 - OlgaDriga
 
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