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Measurements of Hadron Production in d+Au Collisions with the PHENIX Experiment at RHIC. Young Jin Kim University of Illinois at Urbana-Champaign. 2009-02-06. Contents. Introduction Observables in d+Au Nuclear Modification Factor (R dA , R cp ) Angular Correlation (I dA ) PHENIX Detector
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Measurements of Hadron Production in d+Au Collisions with the PHENIX Experiment at RHIC Young Jin Kim University of Illinois at Urbana-Champaign 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Contents • Introduction • Observables in d+Au • Nuclear Modification Factor (RdA, Rcp) • Angular Correlation (IdA) • PHENIX Detector • MPC • 2008 RHIC Run with PHENIX • Summary 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Introduction low x high x • Structure functions are altered in nuclei • x > 0.7: ratio increases, crosses 1.0 • (Fermi momentum smearing) • 0.2< x < 0.7: suppression • (EMC Effect) • 0.05 < x < 0.2: small enhancement • (anti-shadowing) • x < 0.05: shadowing • Saturation? 1. F2D/F2A 1. 0. 0. 1. 1. • Saturation or Color Glass Condensate (CGC) • At low-x there are so many gluons that 2 1 diagrams become important • Nuclear amplification: xAG(xA)=A1/3xpG(xp), • i.e. gluon density is ~6x higher in Gold than the nucleon 0. 0. 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Nuclear Modification Factor (RdA) at RHIC BRAHMS Collaboration, PRL 93, 242303 (2004) PHENIX Collaboration, PRL 98, 172302 (2007) Central Arms: || < 0.35 STAR Collaboration, PRL 97, 152302 (2006) 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Nuclear Modification Factor (Rcp) at RHIC BRAHMS Collaboration, PRL 93, 242303 (2004) PHENIX Collaboration, PRL 94, 082302 (2005) PTH: Punch-through hadrons, HDM: Hadron decay method Backward: -2.2 < < -1.2, Forward: 1.2 < < 2.4 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Nuclear Modification Factor (Rcp) at RHIC PHENIX Collaboration, PRL 94, 082302 (2005) BRAHMS Collaboration, PRL 93, 242303 (2004) PTH: Punch-through hadrons HDM: Hadron decay method Backward: -2.2 < < -1.2 Forward: 1.2 < < 2.4 Observation of suppression in the forward direction. However, alternative explanations exist: Can correlation measurements distinguish between models? 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Angular Correlation D. Kharzeev, E. Levin, and L. McLerran, NPA 748, 627 (2005) π0: <η> = 4.0 h±: |η| < 0.75, Pt > 0.5 GeV/c The evolution between the jets makes the correlations disappear. STAR Collaboration, PRL 97, 152302 (2006) 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
IdAat PHENIX |assoc| < 0.35 Measured two-particle distribution Two-particle acceptance obtained by mixing trigger particles and associated particles from different events PHENIX Collaboration, PRL 96, 222301 (2006) 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
PHENIX Detector • Central Arms: • hadrons, photons, electrons • |η|<0.35 • Δφ=π(2 arms x π/2) • Global Detectors: • Beam-Beam Counter (BBC) • Zero Degree Calorimeter (ZDC) • Reaction Plane Detector (RxNP) • Forward Rapidity Arms: • muons • 1.2<|η|<2.2 • Δφ = 2π Deuteron Au 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
MounPiston Calorimeter (MPC) • Electromagnetic calorimeter using PbWO4 crystal towers • Use to detect neutral pions • South MPC: 196 towers, 3.1 < < 3.7 • North MPC: 220 towers, 3.1 < < 3.9 • ~ 0.010.01(comparable to central arms) 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
PbWO4 Crystal and APD Characteristics of PbWO4 APD Holder PbWO4 Crystal PreAmp APD • PbWO4 crystal: • For use in PHOS detector at ALICE/LHC • Built by Kurchatov group • APD and PreAmp: • From Hiroshima group 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
MPC 2006 - 2008 South North 2006 RHIC Run (200 GeV, 62 GeV polarized p+p): South MPC successfully installed First Result: AN at 62 GeV M. Chiu at Spin 2006 MPC has preformed nicely First MPC result on neutral pion AN at 62 GeV 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
MPC 2006 - 2008 South North 2007 RHIC Run (200 GeV, Au+Au): North MPC successfully installed Reaction plane resolution E.P.{2}BBC+MPC+RXN(SN) E.P.{2}RXN(SN) E.P.{2}RXN-IN(SN) E.P.{2}RXN-OUT(SN) E.P.{2}BBC+MPC(SN) E.P.{2}MPC(SN) E.P.{2}BBC(SN) MPC can help reaction plane reconstruction Several analyses are underway (e.g. di-hadron Ridge, Et distribution) Centrality bin 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
MPC 2006 - 2008 South North 2008 RHIC Run (200 GeV, d+Au, polarized p+p): Upgraded Gain Monitoring System installed 30 times more data taken than 2003 RHIC Run North South 200 GeV p+p Thin black: invariant mass Red: background (by event mixing) Blue: signal Thick black: Gaussian fit on signal 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Neutral Pion Invariant Mass at MPC North MPC d moving out side South MPC Au moving out side 200 GeV d+Au Centrality: 20-40% Thin black: invariant mass Red: background (by event mixing) Blue: signal Thick black: Gaussian fit on signal Analyze MPC data of 200 GeV d+Au, p+p from 2008 RHIC Run Calibration and efficiency estimation are working in progress RdA, Rcp, IdA, MPC-Central arm correlation, MPC-MPC (back-to-back) correlation, etc. 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
PHENIX d+Au Analysis (working in progress) Projection statistical errors for 0+h angular correlation (0) = 3.1-3.9, |(h)| < 0.35 Pt(0) = 1-2 GeV/c, Pt(h)=1-2 GeV/c Projected statistical errors for Nuclear modification factor (Rcp) North MPC (3.1 < < 3.9) d moving out side Arbitrary unit 0-20%/60-88% Pt (GeV/c) 0-h Stay tuned, a lot of RHIC results at QM09 from PHENIX and STAR 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Perspective on PHENIX IdA Rapidity scan is possible Forward/Backward correlation has largest ∆η 2009 Winter Workshop on Nuclear Dynamics 2009-02-06
Summary • Search for saturation at low x is underway • Important input for initial state in HI-collisions! • RHIC results available for 2003 d+Au • observed suppression in forward region • first exploratory correlation measurements • PHENIX and STAR have taken large d+Au data samples in 2008 with new forward detectors enabling correlation measurements with high statistics and over larger rapidity intervals 2009 Winter Workshop on Nuclear Dynamics 2009-02-06