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Identified high pt spectra and Open charm from STAR

Identified high pt spectra and Open charm from STAR. Identified hadrons at high pT dE/dx at relativistic rise p, p Spectra in d+Au, Au+Au (p T >5 GeV/c) Open Charm at RHIC Charm Cross Section and Spectra Compatibility of Current Measurements Need detector upgrades. Zhangbu Xu (BNL)

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Identified high pt spectra and Open charm from STAR

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  1. Identified high pt spectra and Open charm from STAR • Identified hadrons at high pT • dE/dx at relativistic rise • p, p Spectra in d+Au, Au+Au (pT>5 GeV/c) • Open Charm at RHIC • Charm Cross Section and Spectra • Compatibility of Current Measurements • Need detector upgrades Zhangbu Xu (BNL) for the STAR Collaboration Jet Correlations at RHIC Zhangbu Xu (BNL)

  2. Hadron identification: STAR Collaboration, nucl-ex/0309012 Time Projection Chamber: 45 padrow, 2 meters (radius), s(dE/dx)8%, -1<<1 Multi-gap Resistive Plate Chamber TOFr: 1 tray (~1/200), s(t)=85ps Jet Correlations at RHIC Zhangbu Xu (BNL)

  3. Log10(dE/dx) Log10(p) Momentum: GeV/c dE/dx of p (K,p) separation: 2s dE/dx at higher pT Jet Correlations at RHIC Zhangbu Xu (BNL)

  4. STAR Preliminary -(K+p) Separation • Worst Contamination: 1-3% at 50% Eff , 10% at 70-90% Eff • 3 Gauss fits: dE/dx(p)>1.3*dE/dx(K)dE/dx(p) as normal Gauss:s=1, mean=0 • -(K+p) Separation: ~1.5-2 Jet Correlations at RHIC Zhangbu Xu (BNL)

  5. Pion Spectra p+/ p- ratio is about 1 pbar/p ~=0.5 • TPC: • Pion: 0-~0.6GeV/c • Kaon: 0.2-~0.6GeV/c • Proton: 0.2-~1 GeV/c • TPC+TOF: • Pion: 0.-~10 GeV/c • Kaon: 0.2-~3GeV/c • Proton: 0.2-~? GeV/c • TOF: • Pion: 0.2-~1.6GeV/c • Kaon: 0.2-~1.6GeV/c • Proton: 0.2-~3 GeV/c Jet Correlations at RHIC Zhangbu Xu (BNL)

  6. p Nucl. Mod. Factor • RCP h+- 20% higher than p+- pT=3-4 GeV/cconsistent with h/pi ratio • Vitev prediction at dN/dy=650 • TOFr agrees with dE/dx p+- • ISR pp parametrization same as PHENIX • Estimated Syst. Error: 5-10% Jet Correlations at RHIC Zhangbu Xu (BNL)

  7. STAR Preliminary 0.5<|h|<0.9 dE/dx in d+Au@200 Higher  Au+Au@62 h<0 h>0 h+ h- Different particle composition visible!!! Better dE/dx resolution: longer track, shorter drift distance Jet Correlations at RHIC Zhangbu Xu (BNL)

  8. STAR Preliminary |h|<0.5 PRC 70(2004)064907 p+-in d+Au Identified pions similar to inclusive hadrons: Au-side > d-side in all pT (upto 5 GeV/c) Still many things to do in the near future!!! Jet Correlations at RHIC Zhangbu Xu (BNL)

  9. Particle ID above 10 GeV/c Charged hadrons: statistics limited Neutral pions: triggered in EMC (A. Mischke (STAR) nucl-ex/0412045) p+p reference work in progress Jet Correlations at RHIC Zhangbu Xu (BNL)

  10. p-/p+ pbar/p Proton PID at high pT h-/h+ Central Au+Au 200 GeV • dE/dx separation quite large at pT~= 10 GeV/c • Ratios of inclusive hadrons confirm particle compositions and ability to identify particles h+/h- Jet Correlations at RHIC Zhangbu Xu (BNL)

  11. STAR Preliminary central Au+Au 200 GeV O. Barannikova Winter Dynamics2005 PT, GeV/c Antiparticle/Particle Ratios p+/p- ratio constant vs pT p/p ratio consistent with flat in pT Run4 x10 more data: small errors, higher pT Jet Correlations at RHIC Zhangbu Xu (BNL)

  12. STAR Preliminary STAR Preliminary PT, GeV/c PT, GeV/c Baryon Production Central Au+Au 200 GeV Proton (relative) yield decreases rapidly beyond pT=3 GeV/c! pion, proton spectra at high pT; PID jet correlations Jet Correlations at RHIC Zhangbu Xu (BNL)

  13. Effects related to Open Charm Down Down Up Up Down Up Up Down • Radiation Energy Loss • Collision Energy Loss • Dead Cone Effect • Ter-Mikayelian Effect • Transition Radiation • Flow (radial & elliptic) • (quark) Coalescence • Death of “dead cone” All these happen at intermediate pTEmphasize on experimental measurements Jet Correlations at RHIC Zhangbu Xu (BNL)

  14. Charm Total Cross Section Data STAR/PHENIX: x2 (<2s)? Lower Energies: inconsistent? Models: PHENIX: consistent with default PYTHIA,pQCD STAR: >3 above ? Energy dependence mR and mF? Need smaller errors to constrain pQCD and determine the effects in Cosmic Ray Showers X. Dong USTC Can we confirm or rule out Cosmic Ray experiments (Pamir, Muon, Tian Shan) under similar conditions? Pamir, Nuovo Cim 24c (2001) 557; NPB 122(2003) 353c Jet Correlations at RHIC Zhangbu Xu (BNL)

  15. 90% 15% Combine STAR/PHENIX Charm X. Dong USTC STAR: PRL 94(2005) PHENIX p+p (QM04): S. Kelly et al. JPG30(2004) S1189 Discrepancy between STAR and PHENIX should be resolved! J. Stachel, ICPAQGP05 Summary talk No discrepancy? scc=1.10.1  0.3 mb STAR (1.4) PHENIX (0.7) D0 <pT> = 1.3 GeV/c De <pT> ~= 0.5 GeV/c Jet Correlations at RHIC Zhangbu Xu (BNL)

  16. Null Effect at RHIC? • Null Effect of energy loss in Au+Au? • What is missing in this comparison? Reference p+p data! PLB 557 (2003) PLB 560 (2003) Jet Correlations at RHIC Zhangbu Xu (BNL)

  17. X. Dong USTC Electron Spectra STAR: PRL 94(2005) PHENIX Au+Au: PRL 88 (2002); PRL 94 (2005) PHENIX p+p (QM04): S. Kelly et al. 30(2004) S1189 Energy dependence Large dispersion of data STAR/PHENIX p+p, d+Au, Au+Au (STAR) DNP03, QM04, ISMD04 Jet Correlations at RHIC Zhangbu Xu (BNL)

  18. RAA pT (GeV/c) RAA and v2(D->e) PHENIX nucl-ex/0502009 F. Laue (STAR) SQM04 (PHENIX) ICPAQGP05 Collision (over radiation) energy loss? Low pT (scc) binary scaling? Need more statistics and lower syst. And… Jet Correlations at RHIC Zhangbu Xu (BNL)

  19. p + p p + p p + p d + Au d + Au d + Au Where is Beauty? Need precise vertex detector able to measure B decays STAR Preliminary A. Tai, A. Suide (STAR) QM04 hep-ph/0502203 QM05: STAR electron, direct charm in Au+Au Will the same puzzle continue? Jet Correlations at RHIC Zhangbu Xu (BNL)

  20. Moore, Teaney, hep-ph/0412346 Centrality Dependence Total Cross Section matches with hadron yield (pT>~1.5 GeV/c)?Inclusive hadron yield due to FSI Will strong centrality dependence of charm spectral shape affect how we extract charm yield from electron spectra? Direct charm at low pT in Au+Au Jet Correlations at RHIC Zhangbu Xu (BNL)

  21. Electrons at 62.4 GeV Au+Au Electron identification at 62.4GeV Au+Au from run4 Gamma conversion studied in details by reconstructing e+e- pairs at low invariant mass Jet Correlations at RHIC Zhangbu Xu (BNL)

  22. STAR Preliminary STAR Preliminary Photonic background Photonic background matches with inclusive electrons. → Consistent with low charm yield at 62.4 GeV Ready for run4 Au+Au electron spectra Jet Correlations at RHIC Zhangbu Xu (BNL)

  23. Conclusions • Charged hadron identification at high pT can be done with STAR TPC (+TOF) • Au+Au 62.4 GeV • h/p ratios depend on charge, centrality and pT • RCP of h and pions approach each at pT~=5 GeV/c • Au+Au 200 GeV • Identification at high pT possible, p/h ratios decrease at pT>3 GeV/c • Rapidity Asymmetry of pions in d+Au follows closely that of inclusive hadrons • More and exciting results from high pT PID soon. • Charm cross sections measured in p+p, d+Au and Au+Au(soon). • Comparisons to Models and other experiments discussed • Open Charm measurements at RHIC exciting, but also have limitations/puzzles so far. • Vertex detector upgrades needed! Jet Correlations at RHIC Zhangbu Xu (BNL)

  24. Low-mass e+e- Pairs: Prospects at RHIC Need open charm suppression by 5 or measured with +-10% R. Rapp nucl-th/0204003 Jet Correlations at RHIC Zhangbu Xu (BNL)

  25. Pamir EM shower depth With charm XREC upgrade Without charm Pamir, Nuovo Cim 24c (2001) 557 Jet Correlations at RHIC Zhangbu Xu (BNL)

  26. STAR/PHENIX  x2? dN/dy (phi) JG MA: STAR: 6.5, PHENIX: 3.9 Combined: 6.0+-0.4 Jet Correlations at RHIC Zhangbu Xu (BNL)

  27. Charm From STAR Jet Correlations at RHIC Zhangbu Xu (BNL)

  28. Open Charm Spectrum A. Tai QM04 D*/D0 ratio is consistent with other experiments and models Power-law describes the spectrum well up to ~11GeV/c Spectrum is very hard STAR Preliminary Different Measurements at different pT bins. Study the limits on other pT bins? Fantastic!!! But… Jet Correlations at RHIC Zhangbu Xu (BNL)

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