1 / 15

Number of Participants Study

Explore Glauber implementation, error analysis, and results presented by Mike Miller at Yale University. Study central vs peripheral events using Nh-, Npart, Ncoll, b parameters. Consider Woods-Saxon model, numerical calculations, and MC simulation. Discuss NH- mapping, particle production scaling, and cross-section calculations. Insights from STAR analysis meeting highlighted.

jsheridan
Download Presentation

Number of Participants Study

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Number of Participants Study Mike Miller Yale University 7/19/01

  2. Outline • Motivation • Optical based Glauber implementation • Status of current results • Status of error analysis Glauber Working Group (7/19/01)

  3. Motivation • Compare Central events to peripheral • Map Nh- to Npart, Ncoll, b • 2d-Centrality Selection: • ZDC + ? • STAR: • No beam-beam counter (until post AA FY2001), only CTB • ZDC+CTB works only for most central bins • Cannot plot NH- vs. NH-! • Plot NH- vs. Npart! Glauber Working Group (7/19/01)

  4. Year 1 Centrality Selection • Do not want to select on Et, Ncharge • STAR Y1 selection valid only at high centrality • Large improvement in future centrality selection • Is plotting Ncharge vs Npart shady? Glauber Working Group (7/19/01)

  5. Woods-Saxon: from e-A • Overlap Integral: • Sigma: • Binary Collisions: • Participants: General Glauber Theory All as a function of b! Glauber Working Group (7/19/01)

  6. Numerical Calculations • Identical to Kharzeev Glauber Results ~Npart4/3 Glauber Working Group (7/19/01)

  7. “M.C.” Glauber Implementation • Randomly generate b. • Look up probability of interaction. • Use M.C. sampling, decide if interaction takes place. • If interaction, fill histograms with Npart, Nbc Glauber Working Group (7/19/01)

  8. 0-5% 50-60% Mapping NH- to Npart • Map means bin-by-bin • Parameterize (pol2 fit) • Address Fluctuations later Avoid peripheral region Glauber Working Group (7/19/01)

  9. More central Particle Production Scaling Model • Simple assumptions to map b-NH-: • Mean (bin-by-bin) • Dispersion • Statistical Model (Gaussian2) • Parameter: a! Cross section given by integrating over impact Npart with proper weighting. Glauber Working Group (7/19/01)

  10. 69 9.8 132 8 194 6.4 255 5 314 3.4 359 1.8 372 1.1 b(fm) Npart 121 294 481 694 926 1115 1170 Nbc Optical Glauber Results • Restricted to 60% or less centrality => Npart > 35 • Use a=1.2 Glauber Working Group (7/19/01)

  11. Error Analysis • Sigmapp=41+-1 mb => less than 1% effect • Npart vs Ncoll “MC” distribution => less than 4% effect • Deformation => less than 1% effect • 5% Uncertainty in total cross-section: 17% in most peripheral bin, .5% in most central bin “Jiggle” bin boundaries, calculate change in Npart Glauber Working Group (7/19/01)

  12. Results Glauber Working Group (7/19/01)

  13. Results STAR Analysis Meeting (5/01)

  14. Conclusions • Pluses: • No scaling hypothesis • Fluctuations well described with one parameter • Quote Npart > 35 • Error on Npart < 17% • Errors driven by vertex finding inefficiencies, trigger inefficiencies, theory estimate on cross-section • Minuses: • Limited to 60% most central bin • Dependent on Glauber differential cross-section Glauber Working Group (7/19/01)

  15. Click here Glauber Working Group (7/19/01)

More Related