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STAR Run-8 Achievement & Summary

STAR. STAR Run-8 Achievement & Summary. Akio Ogawa for the Collaboration RHIC-AGS Users Meeting 29 May 2008 At BNL. STAR Run8 Goals. Main Physics Goals Gluon saturation in relativistic heavy nuclei Transverse single spin asymmetries of forward p 0

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STAR Run-8 Achievement & Summary

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  1. STAR STAR Run-8 Achievement & Summary Akio Ogawa for the Collaboration RHIC-AGS Users Meeting 29 May 2008 At BNL

  2. STAR Run8 Goals • Main Physics Goals • Gluon saturation in relativistic heavy nuclei • Transverse single spin asymmetries of forward p0 • (Transverse single spin asymmetries of gamma-jet) • (x-dependence of gluon polarization) • Non-photonic electron, Upsilon and D-mesons • Low energy AuAu test run • Detector Upgrades: • Commissioning of pp2pp • Commissioning of Forward Meson Spectrometer (FMS) • Commissioning of DAQ1000 • Commissioning of TOF

  3. STAR Run8 (Modified) Goals • Main Physics Goals • Gluon saturation in relativistic heavy nuclei • Transverse single spin asymmetries of forward p0 • (Transverse single spin asymmetries of gamma-jet) • (x-dependence of gluon polarization) • Non-photonic electron, Upsilon and D-mesons • Low energy AuAu test run • Detector Upgrades: • Commissioning of pp2pp • Commissioning of Forward Meson Spectrometer (FMS) • Commissioning of DAQ1000 • Commissioning of TOF

  4. 1st part • Main Physics Goals • Gluon saturation in relativistic heavy nuclei • Transverse single spin asymmetries of forward p0 • (Transverse single spin asymmetries of gamma-jet) • (x-dependence of gluon polarization) • Non-photonic electron, Upsilon and D-mesons • Low energy AuAu test run • Detector Upgrades: • Commissioning of pp2pp • Commissioning of Forward Meson Spectrometer (FMS) • Commissioning of DAQ1000 • Commissioning of TOF

  5. 2nd part • Main Physics Goals • Gluon saturation in relativistic heavy nuclei • Transverse single spin asymmetries of forward p0 • (Transverse single spin asymmetries of gamma-jet) • (x-dependence of gluon polarization) • Non-photonic electron, Upsilon and D-mesons • Low energy AuAu test run • Detector Upgrades: • Commissioning of pp2pp • Commissioning of Forward Meson Spectrometer (FMS) • Commissioning of DAQ1000 • Commissioning of TOF

  6. STAR Setup 2008 • Particle ID: • MRPC ToF (parts) • Calorimetry: • Photon Multiplicity Detector (PMD) • Barrel EMC • Endcap EMC • Forward Meson Spectrometer • Charged Particle Tracking: • Main TPC • 1/24 with DAQ1000 • Forward TPC (FTPC) • Event Characterization & Trigger: • Beam-Beam Counter (BBC) • Zero Degree Calorimeter (ZDC) • Forward Pion Detectors (FPD)

  7. Why is forward rapidity interesting? • Forward scattering probes asymmetric partonic collisions • Mostly scattering of high-x valence quarks (with known & large polarization) 0.25 < xq < 0.7 on low-x gluons 0.001 < xg < 0.1 Ep p0 qq PN qp N xgpN N =Au xqpN PN qg With heavy nucleus target, gluon density would be even bigger xg ~ few 10-4

  8. p+p and d+Au  p0+p0+X correlations with forward p0 Back-to-back correlation PRL 97, 152302 BRAHMS STAR Conventional shadowing will change yield, but not angular correlation Coherent effects such as CGC evolution will change the angular correlation Sensitive to xg ~ 10-3 in pQCD scenario; few x 10-4 in CGC scenario.

  9. Run8 integrated luminosity at STAR Diamonds show data taken with a broad range of HV settings dAu Slow Luminosity (nb-1) Original goal Final total: 49 nb-1 Triangles are with final or near-final PMT gains Reduced goal dAu Integrated Luminosity (nb-1) Also have ~660M FMS+fast-detector minbias events Goal 9 pb-1 Sampled 7.8 pb-1 87% of goal pp CGC reference data

  10. Forward single-spin asymmetries in STAR arXiv:hep-ex/0801.2990 • Large transverse single-spin asymmetries at large xF • xF dependence matches Sivers effect expectations qualitatively (but not quantitatively) • pT dependence at fixed xF not consistent with 1/pT expectation of pQCD-based calculations

  11. Forward single-spin asymmetries • Acceptance of FMS and projected RHIC performance will enable… • Further reach for inclusive p0 and heavy mesons • Spin-dependent near-side correlations (p0-p0)  separation of Sivers and Collins effects • Spin-dependent away-side correlations (p0-jet)  isolation of Sivers effect • Embark on spin-dependent inclusive g and g+jet Projections for 9 pb-1 P=70%

  12. AN and Sivers and Collins effect Sivers mechanism:Correlation between nucleon spin and parton kT Collins mechanism:Transversity (quark polarization) * asymmetry in the jet fragmentation Phys Rev D41 (1990) 83; 43 (1991) 261 Nucl Phys B396 (1993) 161 SP SP kT,π Sq kT,q p p p p Sq kT,π Asymmetry in jet/photon production Asymmetry in hadrons in jets Both effects can contribute to inclusive π0 AN Need to go beyond inclusive π0 detection to separate them jets and direct photons, orπ-πcorrelation in a jet

  13. Transversely Polarized p+p FoM (P2L) at STAR Integrated FMS FOM P2L (nb-1) Goal 3.8 pb-1 Sampled 1.6 pb-1 Using reported CNI values Only 43% of goal, after calibration from jet • Extend xF and pT range for forward single-spin asymmetries • Separation of Collins and Sivers • Significant extension, but well short of what we had intended to achieve • Study direct photon asymmetries in forward direction • Probably not practical with the current limited data set

  14. FPD to FMS Run3-5 FPD Inclusive p0 cross sections AN for inclusive p0 production RUN3 dAu =only one module (South) At deuteron side (west) Inclusive p0 cross sections in dAu and RdA Forward-mid rapidity particle correlations

  15. FPD to FMS • Run8 and beyond: FMS • FMS will provide full azimuthal coverage for range 2.5  h  4.0 • broad acceptance in xF-pT plane for inclusive g,p0,w,K0,… production in p+p and d(p)+Au • broad acceptance for g-p0 and p0-p0 from forward jet pairs to probe low-x gluon density in p+p and d(p)+Au collisions 47 x more area > Order of magnitude more luminosity d Au

  16. Students prepare cells at test Lab at BNL Total number of undergraduate students = 10 Total number of graduate students = 5 Forward Meson Spectrometer (FMS) New FMS Calorimeter Lead Glass From FNAL E831 804 cells of 5.8cm5.8cm60cm Schott F2 lead glass Loaded On a Rental Truck for Trip To BNL

  17. Forward Meson Spectrometer for Run8 First pi0 reconstruction of FMS events in Run8 (Calibration is underway) Small Cell PSU Type 224 of 476 QT board Cockcroft-Walton HV bases with computer control through USB. Designed/built in house for FEU-84. • Readout of 1264 channels of FMS provided by QT boards. Each board has • 32 analog inputs • 12-bit ADC / channel • 5-bit TDC / channel • Five FPGA for data and trigger • Operates at 9.38 MHz and higher harmonics • Produces 32 bits for each RHIC crossing for trigger Designed and built at Penn State University Designed and built at UC Berkeley/SSL

  18. Calibration is ongoing Adjust gain for each detector by high tower sorted Mgg (1264 Mggplots) Need multiple iteration through the data since pion and photon energy get spread over several towers. Run 6 resolution of d(Mp)/Mp~10% should be possible.

  19. Calibration is ongoing Minimal run-by-run dependence in mass peak observed MIT (LED optics) UC Berkeley/SSL (flasher boards) Texas / Protovino / BNL (assembly) SULI program (Stony Brook students) / BNL (control electronics) Calorimeter stable at level of ~1%. LED system : critical calibration tool Entire Run 8 data set should become quickly available with final calibration.

  20. FMS Summary and Future • Forward Meson Spectrometer (FMS) is constructed & took data in run8! • Low-x physics (Can we see Gluon saturation? CGC?) • Separate Sivers from Collins • “Jet-like” events, or pi0-pi0 • Near and away side jet-pi0 correlations • Heavier mesons? • Eta, Ks, J/psi… • With Future running, Direct Photon + Jet to test “sign change” • of Sivers function

  21. Heavy Flavor Physics in Run8 • High-precision non-photonic electron • SVT+SSD removed ~ x10 reduction of BG • Staged L0 Trigger: • d+Au : ~90x statistics (run3) • p+p : ~30x statistics • ϒ • d+Au L2 trigger sampled 35 nb-1 • expected yield: ~ 240 • (separation of 3 S states unlikely) • D0 • d+Au Minimum bias dataset: 46 M events • >2x statistics from previous d+Au run3

  22. Removal of SVT+SSD : Impact on Heavy Flavor NP Electrons in STAR: Inclusive/Background • Largest Background source on inclusive electrons so far: Conversion electrons from SVT+SSD material • SVT/SSD removed (Run8) Radiation length reduced ~1/10 • Compare the e/h ratio to run3 corresponding results, we find inclusive electrons decrease to ~ 0.10 • Less material decreases relative error by factor ~10 Electron hadron ratio run8/run3 • Charm production via NPE(EMC), D0, TOF (e and muon) are all consistent • Next crucial check: NPE with reduced material by order of magnitude Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10. Compare the e/h ratio to run IIIcorresponding results, we find inclusive electrons decrease to 0.10.

  23. d+Au & pp integrated luminosity at STAR MinBias usable Events High Tower Integrated Luminosity Goal = 30 Mevts Goal = 30 nb-1 Recorded 46 Mevts Sampled 36 pb-1 153 % of goal 120 % of goal dAu dAu pp “slow” Luminosity (nb-1) MinBias Vertex (Z) Distribution Goal 4.5 pb-1 Sampled 3.1 pb-1 69% of goal pp 92% have Vz  50 cm

  24. Low Energy (9 GeV) Test Run • Find Collisions  • Gain understanding of triggering issues  • Determine Luminosity  Luminosities ~ 1 to 3 x 1023 cm-2 s-1 Collisions rates =  x L = (6 b)(1.5 x 1023 ) = ~ .9 Hz Our present understanding of our trigger efficiency, and Angelika’s luminosity, agree very well (~ 20%)!

  25. STAR preliminary STAR preliminary STAR preliminary Au+Au @ √sNN=9 GeV: Preliminary Analysis Raw multiplicity Note: Plots should be taken only as illustrative of data quality and analysis capability PID (dE/dx only) Uncorrected p⊥ spectra George Stephans’s Talk on Friday

  26. DAQ1000 commissioning Laser event (plus pileup) Replace full TPC readout chain to record full delivered luminosity Dead-time ~ 0 Data taking speed ~x10 Preliminary calibration shows dE/dx resolution and noise better than old electronics. • One sector of the TPC (1/24) instrumented with DAQ1000 electronics • Commissioned/integrated and took part of physics data taking by early run8 • Routine operation at 250 Hz with TOF triggered events • Speed test: operated at 1 kHz with only 5-7% dead time (<<100 us/event) • On schedule to full implementation for run9

  27. Multi-gap Resistive Plate Chamber Time-of-Flight Joint project between USA & China In detector research 1 tray in some of runs 2-7 5 trays in run 8 behind DAQ1000 ~75% in run 9 100% in run 10 (Q2,FY09) -0.9<h<0.9, 0<f<2p 23,000 ch (120 trays) e Posters by Zebo Tang and Jin Fu • Total TOF triggered events 76M for physics and calibration in p+p • Provide crucial information for pileup rejection • Preliminary calibration : 81ps (goal <100ps) • TOF+TPX from run8: • Non-photonic electron at low pT with low material • 25x statistics for PID spectra in p+p • >10x S/B ratio of Resonances (f,K*) in p+p

  28. For the future: pp2pp @ STAR • Roman pots installed east and west downstream of STAR (thanks, C-AD!) • pp2pp data acquisition integrated into STAR trigger and DAQ systems • Inserted Roman pots into the beam pipe during last 2 hours of p+p run • Observed pp2pp detector rates as expected • No impact on background levels in STAR mid-rapidity detectors • Physics in Run 9

  29. STAR Run8 Goals & Luminosity

  30. STAR Run8 Summary • Main Physics Goals • Gluon saturation in relativistic heavy nuclei • Transverse single spin asymmetries of forward p0 • (Transverse single spin asymmetries of gamma-jet) • (x-dependence of gluon polarization) • Non-photonic electron, Upsilon and D-mesons • Low energy AuAu test run • Detector Upgrades: • Commissioning of pp2pp • Commissioning of FMS • Commissioning of DAQ1000 All 3 used for Physics • Commissioning of TOF Short run didn’t allow us to complete some of original goals “Short” run8 was successful Exciting physics will be coming out

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