Yale RHIG High pT Contributions

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Yale RHIG High pT Contributions
Boris Hippolyte 1st year postdoc Jon
Gans 5th year grad Michael Miller 5th year
grad Oana Catu 2nd year grad Christine
Nattrass beginning grad John Harris Physics
Leader
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What were doing now Physics
Yale RHIG primary authored high pT papers

• C. Adler et al. Multiplicity distribution and
  spectra of negatively charged hadrons in AuAu
  collisions at sqrt(s_NN)130 GeV Phys. Rev.
  Lett. (87), 112303 (2001)
• C. Adler et al. Centrality Dependence of High pT
  Hadron Suppression in AuAu collisions at
  sqrt(s_NN)130 GeV Phys. Rev. Lett. 89, 202301
  (2002) nucl-ex/0206011.
• C. Adler et al. Disappearance of back-to-back
  high pT hadron correlations in central AuAu
  collisions at sqrt(s_NN)200 GeV Phys. Rev.
  Lett. 90, 082302 (2003)
• J. Adams et al Evidence from dAu measurements
  for final-state suppression of high pT hadrons in
  AuAu collisions at RHIC Phys. Rev. Lett. 91,
  072304 (2003)
• J. Adams et al., Transverse momentum and
  collision energy dependence of high pT hadron
  suppression in AuAu collisions, submitted to
  Phys. Rev. Lett.
• J. Adams et al., Multi-Strange Baryon Production
  in AuAu collisions at sqrt(s_NN)130 GeV,
  submitted to Phys. Rev. Lett.
• M.L. Miller and R. J. Snellings Understanding
  the effect of Geometry Fluctuations on High pT
  Elliptic Flow Measurements at RHIC To be
  submitted to Phy. Rev. Lett.

2002-2003 11 invited and 5 contributed high-pT
presentations (Gans, Hippolyte, Miller)
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Why Jets? Energy Loss in Dense Matter
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Yale High pT Focus

• Identified particle yields pion, kaon, proton
  spectra with RICH detector (B. Hippolyte)
• Inclusive charged particle yields hh-
  spectra (J. Gans)
• 2-particle high pT hadron correlations jet,
  di-jet structure and yields (M. Miller, O. Catu,
  C. Nattrass)
• Topological Jet ID tagged jet, di-jet spectra.
  (Identified particle) Fragmentation function
  measurements (all)

Show all in 15 minutes? No chance!
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Identified Hadron Spectra from RICH
Chemical properties temperature, chemical
potential, flow Soft vs. Hard Physics Sensitive
to gg, qg, qq contributions
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Identified Hadron Spectra from RICH
Chemical properties temperature, chemical
potential, flow Soft vs. Hard Physics Sensitive
to gg, qg, qq contributions
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200 GeV Charged Hadron Spectra

• pp spectrum first at 200 GeV
• High event rate, backgrounds vertexing bias gt
  Problems solved by J. Gans

• pp absolutely normalized
• Methods/solutions applicable in dAu

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Charged RAA Comparison to Theory

• pQCD
• Vitev and Gyulassy, PRL 89, 252301
• XN Wang, to be published (see also
  nucl-th/0302007

pQCD good agreement gluon density 15 x cold
nuclear matter
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Charged RdAu Turning off Final State
Jons Thesis Cover

• No suppression for minimum bias dAu
• No suppression for central dAu
• Whats happening At pTgt8 GeV/c?

High pT Suppression is a Final State Effect!
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First Observation of Jets at RHIC
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Jets In Most Violent Collisions
Disappearance of away-side jet is a Final State
Effect! Jet Quenching
Adams et al., Phys.Rev.Lett. (91)072304,2003
Mikes Thesis Cover
Background subtracted
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Where are we? Where to go?

• Jets at RHIC are now well established, excellent
  probe of medium
• Produce strongly interacting, highly opaque
  matter
• High pT suppression is most likely post-hard
  scattering phenomenon
• Tagged jet fragmentation
• distinguish hadronic vs. partonic E-Loss
• Jet triggered data in pp, dAu (Oana and
  Christine in progress)

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Yale Contributions to STAR High pT
Software
Hardware

• New global reco software (Miller)
• RICH Reco (Hippolyte)
• New V0 reco software (Betty, Caines, Hippolyte)
• Database and calibrations (Gans)
• Vertexing software (Gans, Miller)
• Jet finding software (Miller)
• SVT Software (Betty, Caines, Salur)

• SVT hardware (Caines)
• STAR II Hardware (Smirnov)
• Forward Tracking upgrade (Smirnov, Miller/MIT)