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A nose-cone electromagnetic calorimeter for PHENIX – physics

A nose-cone electromagnetic calorimeter for PHENIX – physics. Richard Seto University of CA, Riverside DC Upgrades meeting Nov 14, 2003. Low-x physics (CGC, CQF, etc). New theoretical ideas in Low x region. Collisions with nuclei act as an amplifier (RHIC is unique)

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A nose-cone electromagnetic calorimeter for PHENIX – physics

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  1. A nose-cone electromagnetic calorimeter for PHENIX – physics Richard Seto University of CA, Riverside DC Upgrades meeting Nov 14, 2003 R. Seto

  2. Low-x physics (CGC, CQF, etc) New theoretical ideas in Low x region. Collisions with nuclei act as an amplifier (RHIC is unique) Direct measurement of gluon distribution via Direct photon Heavy Flavor What must we do? Measure muons/photons at forward angles What will improve PHENIX? Measure electrons at forward angles Muon trigger, nosecone calorimeter The Colored Glass Condensate (shadowing?) Classical Approx Robust calculations in QCD using “renormalization group” methods Depends on a single scale QS They make testable predictions! Mueller, Kharzeev, Strickman, Qui, Fries, Vitev, Jalalian-Marion High x xG(x) x low x R. Seto

  3. The system at RHIC… 100 10 Energy Density (GeV/fm3) 0.1 0.1 1 10 Time (fm) R. Seto

  4. What is the Initial State of a Relativistic Heavy Ion Collision? A CGC? 100 10 Energy Density (GeV/fm3) 0.1 0.1 1 10 Time (fm) R. Seto

  5. Colored Glass Condensate? 100 10 Energy Density (GeV/fm3) 0.1 0.1 1 10 R. Seto Time (fm)

  6. To a QGP? 100 10 Energy Density (GeV/fm3) 0.1 0.1 1 10 Time (fm) R. Seto

  7. Regions(or what I learned in Urbana) RdA Rises w/ Npart Cronin Shadowing: Higher twist RdA ~1 (???) Rises w/ Npart (Nbin) No Cronin CQF Quantum evolution via anomalous dimension 10-4 Y~4 • RdA <1 • Falls with Npart • No Cronin • Shadowing: • Leading twist CGC Purely classical – tree level only 10-3 Y~2 1/x Y~0 10-2 CGC boundary QS2=QS(y=0) 2ey ~0.3 CQF boundary QS2=QS(y=0) 4 pQCD Qs 10-1 QCD 1 100 1 10 Q (GeV) R. Seto

  8. How do you experimentally see saturation? e, e, * ? • Look at Gluon Structure Functions at low-x • Ask Dima, Al, Jamal etc to calculate • pA (in order of preference?) • *, ee • Direct photons • Open Charm • J/ production • Evolution of quark structure functions with Q2 – use Drell- Yan as a probe ? • X ~ 1 to 10-4 (evolution) • Q2 ~ 1 (saturation) to 50 (pQCD) • Functions of • Y= 0 to 4, pT=0 to 10 GeV • Centrality • Map out previous diagram R. Seto

  9. pA at RHIC Need pp to “Normalize” dA run AA run (?) Run Various Nuclei to chart out effects Lower energies? Schedule ? RHIC II ? ? R. Seto

  10. The Nosecone Calorimeter/Tailcatcher Tailcatcher NoseconeCalorimeter • Nosecone • EM calorimeter • (~20-50 X0) • Tungsten w/ Silicon readout • Tailcatcher • Crude Hadronic calorimeter • behind magnet or • Back end of nosecone • Cu or stainless 5 Edward will cover this in more detail R. Seto

  11. A more accurate picture Tailcatcher NoseconeCalorimeter R. Seto

  12. What do we hope it can do • Direct photons to  ~ 2.4, xA to 10-3 (8 to 43) • Electron pairs, to complement muon pairs for * • Can get to high y? • e pairs (charm, bottom) • 0,0 • Determination of event kinematics? • Crude Reconstruction of jet direction and energy together with forward Si detectors • Offline identification W’s from jets? • Information for first level trigger? R. Seto

  13. Coverage in x2 Q2 • Assume dA run • 109 sampled min bias events • Black lines coverage of >100 events (red >1000) • (logx)=.1, Q2=1 GeV2 • Good coverage to xA~10-3 PT~1GeV PT~2GeV R. Seto x2

  14. Measuring x2 • For a given E and pT of the photon, xA is fairly flat • Crude measurement of jet is will determine xA R. Seto

  15. Can we measure Q2, xp? E=15, pT=3 E=15 Log x1 Q2 E=10, pT=3 E=10 E=15, pT=2 E=5 Ejet(GeV) Ejet(GeV) R. Seto

  16. Detecting Jet w/ Direct photon • For xA=5x10-3 • Require Jet w/ direct  to be > 10 GeV. • Jet angle < 20 degrees • Can we reconstruct a 10 GeV Jet? • Can we separate it from the beam fragments? GeV Jet Energy vs Angle GeV R. Seto  Energy vs Angle

  17. Resolving ’s from 0’s 40 • PT to 5 on the inner radius • 4mm “2 track resolution” PT  (GeV) Inside radius - E PT(GeV) 20 =1 (outside radius) =2.5 (inside radius) 0 .5 0 1  “2 track” Resolution (cm) R. Seto

  18. Questions • How well can you identify direct photons? • I.e. how well can you find0 • Can we find an isolation cut that works? • How high in y can we go with electron/muon pairs? (guess by hand xA~5x10-4) • How well can you measure xA,xp, Q2? • How well can you measure hadronic jet? • How well can we recover muon resolution? • Triggers? • Can we understand recoil “stuff”? • How important is adding photons, lepton pairs, single leptons, vs hadrons in mapping out the effect? (do we have the right kinematical reach – too high x, or too low pt(at high y)?) R. Seto

  19. PHENIX: electrons,muons, photons, hadrons 2 Arm central spectrometers + 2 muon endcaps -0.35< <0.35 (e,, hadrons) 1.2<| |<2.5 (muons-2nd year) High resolutionTracking Particle ID Global Detectors (centrality) Zero Degree Calorimeters (ZDC) Beam-Beam Counter (BBC) Central Magnet CentralArms Muon ID Muon Magnet Beam R. Seto

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