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Plans for the first Jet Paper

Plans for the first Jet Paper. PWG04 August 24 th 2009. Christian Klein- Bösing for the PWG04 Task Force. A Short , Early P aper on Charged J et R econstruction in p+p ?. Want a maximum of statistics Statistical precision Systematic studies

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Plans for the first Jet Paper

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  1. Plans for the first Jet Paper PWG04 August 24th 2009 Christian Klein-Bösing for the PWG04 Task Force

  2. A Short, Early Paper on Charged Jet Reconstruction in p+p? • Want a maximum of statistics • Statistical precision • Systematic studies • Depend on understanding of high pT tracking • High pT spectra needed first • But even if the paper will be not “short” or “early” the following should give you an idea of the key points Not in the timescale of a few weeks Christian Klein-Bösing

  3. Title • Inclusive Jet Production and Jet Fragmentation • in p+p collisions at 7 TeV/10 TeV • Measured with Charged particles in the ALICE Experiment Christian Klein-Bösing

  4. Beam Energy/Luminosity PYTHIA8 simulation + fastjet (R = 0.7) 10 TeVp+p 7 TeVp+p Here only MB events, luminosity more relevant when triggering, (But pileup effects depend on luminosity and bunch pattern). 109 ≈ 20 d × 60% × 1 kHz Christian Klein-Bösing

  5. Rough Abstract Christian Klein-Bösing

  6. Figures and Tables • Fig. 1: Response matrix • MC all vs. MC charged • MC charged vs. rec • Fig. 2: • Fragmentation function (for charged jet) • Comparison to MC and MLLA • Fig. 3: • Jet spectrum, corrected up to charged jet energy • Unfolded to total jet energy (for different cuts in z of the leading jet) Christian Klein-Bösing

  7. Fig. 1 • Response Matrix • Emphasize the two levels of corrections to reconstructed jets • Charged track jet → charged particle jet → all particle jet MC (all R = 0.4) MC (ch. R = 0.4) MC (ch. R = 0.4) Rec (R = 0.4) Christian Klein-Bösing

  8. Fig. 2 • Bias of the charged jet reconstruction • Reduced when using dijets (TODO) • Compare to different fragmentation models • PYTHIA (string) • HERWIG (cluster) • Also differ in UE • TODO • At low ξ comparable to calculations (e.g. MLLA) without corrections? • Influence of UE • TODO • pT,jet> 40 GeV most relevant for comparison with Pb+Pb Leading jet fragmentation for R = 0.4 (LHC09a1-3) Christian Klein-Bösing

  9. Fig. 3 • Raw spectrum corrected for detector effects (charged jet spectrum) • Fully corrected total jet spectrum • Different subsamples of jets corrected to full • Different leading particle z (TODO) Christian Klein-Bösing

  10. Tables • Table 1: • Examples for reconstructed momentum shift and smear due to: • Limited Cone radius • Charged to neutral • MC to reconstruction • Table 2: • Systematic uncertainties TODO Christian Klein-Bösing

  11. Rough Layout Christian Klein-Bösing

  12. What Needs to Be Done • Systematic uncertainties • Jet Momentum scale checks • Flavour dependence, biases (cuts on jet shapes) • Corrections • Revisit unfolding procedure: variable bin size, regularization • Underlying event in multiple collisions • High pTQA • cannot rely on jet spectrum if single particle spectra are not understood • Connection to MB data → coordinate QA • Sharpen focus on fragmentation • Comparison to generators (i.e. PYTHIA: Lund Fragmentation, HERWIG cluster fragmentation) and theory • Analysis note Christian Klein-Bösing

  13. Momentum Scale • Induced by JF • Cone radius/R-parameter • Bias • Algorithms • Can be studied with data alone • Correlations • Average energy in certain “trigger-bin” compared to mean momentum • Should be symmetric in η-φ: otherwise acceptance effects • 2D correlation TODO • Also handle on UE contribution • Induced by reconstruction • QA, high pTspectra Charged particles correlated with leading jet axis Christian Klein-Bösing

  14. High pTQA: Cuts Improved cut on 1/pT uncertainty (relative) loose cuts B. Bathen loose cuts + relpT error Christian Klein-Bösing

  15. People from thePWG4 Task Force • Jet Spectrum • Unfolding: CKB, YdaliaDelgado • Jet Finders • FastJet: S. Jangal, M. Estienne, J. Thäder, O. Busch • Deterministic Annealing: D. Perrino • Di-jets: D. Perrino • Fragmentation function: B. Bathen, V. Roman • Jet shape/topology: S. Pochybova. L. Molnar • Underlying event: A. Abrahantas, E. Lopez, S. Valero, A. Agosc • High pT QA: G. Barros (M. Munhoz), M. Verweij (M. van Leeuwen), B. Bathen Christian Klein-Bösing

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