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FTPC Status and Results Summary: Calibration and Data Quality Updates

This summary provides an overview of the FTPC’s calibration changes and data quality improvements, including updates on AuAu and dAu data, vertex reconstruction, particle spectra, centrality definition, and strangeness measurements. It covers improved hardware setup, better data resolution, and successful event captures. The text discusses data quality assessments, cross-checks, and readiness for physics studies, along with detailed analysis results and comparisons between different particle behavior observations. Additionally, the text mentions the FTPC’s role in forward/backward correlation studies, string fusion models, and flow calculations. Overall, it highlights the FTPC's significance in enhancing data quality and analysis capabilities for experimental physics research.

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FTPC Status and Results Summary: Calibration and Data Quality Updates

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  1. FTPC status and results Summary of last data taken AuAu and dAu calibration : Data Quality Physic results with AuAu data Spectra Flow Physic results with dAu data Centrality definition Strangeness

  2. FTPC successfully took ~20 106 dAu events and 8 106 pp events Changes since last AuAu/pp (2001-2002) run Increased gain Better resolution Frisch grid grounding problem fixed Better residuals Summary of RunIII + STAR Coll. Meeting, August03

  3. uncorrected corrected rstep [cm] Inner cathode shift correction applied and works with reasonable precision. hardware sector Data quality AuAu data AuAu data Vertex reconstruction with FTPC tracks with respect to TPC vertex : x,y ± 200 um AuAu data x,y ± 600 um dAu data dAu data

  4. Data quality II Cross-check: pT and dca for primaries in different sectors (j regions) Track parameters do not show any systematic effects. FTPC ready for physics!

  5. 1/Nevent dN/(pt dpt) [1/GeV2] <pt>west=0.409+-0.0077 GeV <pt>east=0.394+-0.0078 GeV pt [GeV] AuAu Minbias pT spectra • Charged particles • AuAu minbias • 68k (47k) • No corrections • Quality Cuts: • dca < 2.0 cm • 0.1 <= pT < 1.0 GeV/c • 3.0 <= |yp|< 3.2 • Nhits >= 5 • |vertexz| <= 25 cm FTPC West FTPC East STAR Coll. Meeting, August03

  6. FTPC pion acceptance STAR Coll. Meeting, August03

  7. <pt> [GeV/c] FTPC west FTPC east centrality bin AuAu: <pT> vs centrality • Charged hadrons <pT> increase slightly with centrality • Same behaviour as for charged particles at central rapidity (TPC) • <pT> calculated from power law fit in range pT [0.1,1.0] GeV/c • No corrections • Quality Cuts: • dca < 3.0 cm • 0.1 <= pT < 1.0 GeV/c • 2.8 <= |h|< 3.8 • Nhits >= 5 • |vertexz| <= 25 cm STAR Coll. Meeting, August03

  8. AuAu: <pT> vs |h| • Charged hadrons <pT> decrease slightly with pseudo-rapidity • Similar behaviour as seen by NA49 and BRAHMS Charged hadrons <pT> with |pseudorapidity| • <pT> calculated from power law fit in range pT [0.1,1.0] GeV/c • No corrections • Quality Cuts: • dca < 3.0 cm • 0.1 <= pT < 1.0 GeV/c • 2.5 <= |h|< 3.5 • Nhits >= 5 • |vertexz| <= 25 cm <pt> [GeV/c] FTPC west FTPC east STAR Coll. Meeting, August03 |Pseudo-rapidity|

  9. Overlapping of two color strings  • 3 independent regions can be distinguished : • regions 1,2 no overlapping color field = color field of a single string • overlap region 3 with color field of both strings summed Particle multiplicity is decreased while pT is enhanced  Forward/Backward correlations. Projection of two overlapping strings onto the transverse plane AuAu: forward-backward correlation String fusion model • color strings = (small) areas in transverse space • can overlap, forming clusters (percolation) One observable: Forward/Backward <pT> correlation[Eur. Phys. J. C 16, 349-359 (2000)] Monte-Carlo model PSM 1.0 [Eur. Phys. J. C 22, 149-363 (2001)] STAR Coll. Meeting, August03

  10. AuAu: forward-backward pt correlation The min. bias data do not show strong correlation (preliminary) < pT > = mean pT per event Forward;  = [2.8,3.8] Backward;  = [-3.8,-2.8] FTPCs sensitive and a good tool to study long range forward/ backward correlations STAR Coll. Meeting, August03

  11. Pt vs |h| efficiency AuAu: Embedding FTPC embedding has just taken off!! Thanks Eric! AuAu min. bias embedding * p with pT flat [0., 2.0] * 10% of TPC multiplicity within |h| = [2.8,3.8] efficiency nicely constant ~ 80% STAR Coll. Meeting, August03

  12. v2 (%) h AuAu: Flow, v2 cumulant method V2 calculation with cumulant method with TPC+FTPC particles • Results unaffected by the missing sector (this method allows higher statistics). • Cumulant method with 4 particles removes non-flow effects in v2 • Non-flow effects seem to be ~ 1% in TPC rapidity • Non-flow effects do not affect FTPC region ? STAR Coll. Meeting, August03

  13. h pT (GeV/c) AuAu: v2 and FTPC Cumulant method with 2 particles correlation can be used to determine v2 with FTPC ALONE!! • v2 vs h and • v2 vs pT Good agreement with FTPC+TPC!

  14. STAR sqrt(s)=200 • PHOBOS sqrt(s)=130 • STAR sqrt(s)=200 • PHOBOS sqrt(s)=200 AuAu: v2 comparison V2vsh from STAR in comparison with PHOBOS data at 130 GeV and 200 GeV FTPC is involved in other flow studies: V1, V2 with event plane method, Higher harmonics (Markus O. Aihong T. and Art P. work) See Art P.’s talk on Saturday

  15. dAu: FTPC defines centrality HIJING simulation shows a correlation between the impact parameter and the FTPC East multiplicity Hijing simulation 50k dAu minbias z-Vertex <= |60| cm FTPC data are used for STAR centrality definition

  16. dAu: Strangeness, Ls * L p p- (63.9%), mL=1115.7 MeV, ct=7.89 cm * Study all pos-neg pairs, assuming p mass and p mass (FTPC measures charge but no particle Id). * Geometrical cuts for pairs Decay length > 10 cm Pair dca < 2.5 mm Proton-like dca [0.1, 2] cm Pion-like dca > 1.5 cm • Background estimation with rotated tracks: • Every track is rotated 180o in j and combined with all non-rotated tracks with opposite charge • Same event characteristic, (mult, flow, vertex) STAR Coll. Meeting, August03

  17. L Real pairs Background pairs Real pairs Background pairs L L L dAu: L andL signal 5.8 M events dAu min bias in FTPC West only (better calibration) L yield = ~4000 Row RatioL/ L = ~0.47 L yield = ~1900 Hijing L/ L ratio = 0.64 and with same cuts = 0.46 STAR Coll. Meeting, August03

  18. Summary • AuAu, dAu, pp data with the FTPC available. • Calibrations : AuAu complete, dAu near final, pp is being checked by Mirko P. • First physics results on flow. • Preliminary uncorrected charged particle spectra and L andL yields. • Embedding is in progress for efficiency determination. • FTPC available for data taking in Run IV. STAR Coll. Meeting, August03

  19. FTPC group • Volker Eckardt • María Mora Corral • Markus Oldenburg • Jörn Putschke • Janet Seyboth • Peter Seyboth • Frank Simon … and lots of help from STAR people, specially : Eric, Jerôme, Lidia, Jeff … STAR Coll. Meeting, August03

  20. FTPC pion acceptance STAR Coll. Meeting, August03

  21. AuAu efficiency STAR Coll. Meeting, August03

  22. dAu efficiency |vertexz| < 20cm STAR Coll. Meeting, August03

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