PHENIX Beam Use Presentation

1

• PHENIX Beam Use Presentation
• W.A. Zajc
• for the PHENIX Collaboration
• ( this talk available at http//www.phenix.bnl.gov
  /phenix/WWW/publish/zajc/sp/presentations/rbupaug0
  2/PACAug02.htm )

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Beam Use Proposal

• Requested input
• Desired beam run segments
• Physics from same
• Collaboration/experiment status
• A note on nomenclature
• Run-1 ? Summer-2000 Au-Au run at 130 GeV
• Run-2 ? 2001/2002 Au-Au/p-p at 200 GeV
• Run-3 ? Upcoming (FY03) run

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Run Request at a Glance

• Run-3
• d-Au 16 weeks (10 weeks data-taking)
• p?-p? 8 weeks ( 3 weeks data-taking)
• Run-4
• Au-Au N weeks (definitive J/Y measurement)
• p?-p? 26-N weeks ( DG measurement)
• Run-5
• Si-Si (Light ions with sufficient ?L dt
  to measure J/Y)
• p?-p? (Towards 320 pb-1 at 200 GeV)
• Notes
• Predicated on Roser model ? 3 modes deprecated
• All running is assumed at vsNN 200 GeV, with
  possible exception of development work towards
  500 GeV for polarization

4
The Collaboration

• A strongly international venture
• 12 nations
• Brazil, China, France, Germany, Hungary, India,
  Israel, Japan, South Korea, Russia, Sweden,
  United States
• 57 institutions

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Recent Additions

• Peking University
• Hungary
• KFKI Research Institute for Particle and Nuclear
  Physics
• Debrecen University
• Elte University, Budapest
• University of Colorado
• University of Illinois Urbana-Champaign
• Saha Institute / Jammu University
• (In progress)

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Run-1 Configuration

• Two central arms
• Mechanically complete
• Roughly half of aperture instrumented
• Global detectors
• Zero-degree Calorimeters (ZDCs)
• Beam-Beam Counters (BBCs)
• Multiplicity and Vertex Detector (MVD,
  engineering run)

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Run-1 Publications (1)

• Centrality dependence of charged particle
  multiplicity in Au-Au collisions at ?sNN 130
  GeV, PRL 86 (2001) 3500
• Measurement of the midrapidity transverse energy
  distribution from ?sNN 130 GeV Au-Au collisions
  at RHIC, PRL 87 (2001) 052301
• Suppression of hadrons with large transverse
  momentum in central Au-Au collisions at ?sNN
  130 GeV, PRL 88, 022301 (2002).
• Centrality dependence of p/-, K/-, p and pbar
  production at RHIC,PRL 88, 242301 (2002).  
• Transverse mass dependence of the two-pion
  correlation for AuAu collisions at ?sNN 130
  GeV, PRL 88, 192302 (2002)
• Measurement of single electrons and implications
  for charm production in AuAu collisions at ?sNN
  130 GeV,PRL 88, 192303 (2002)

1st study of dN/dh vs Npart
1st measurement of ET
1st measurement of high pT suppression
1st measurement of high pT particle yields
1st measurement of source size at high pT
1st measurement of open charm yields
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From Run-1 to Run-2
Run-1 (2000)

• For 2001 Run

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Run-2 Results

• All central arm detectors instrumented and
  working
• South Muon Arm commissioned first physics
• Implementation of Level-1 and Level-2 physics
  triggers
• Dramatic extension of our reach in transverse
  momentum

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PHENIX at QM02 A Sample of all Run-2 results

 
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Run-3 and Beyond
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DAQ and Trigger

• PHENIX has made a major effort to
• Design and build a system capable of extracting
  all physics at design luminosity
• Triggers commissioned, used in Run-2, extended
  for Run-3

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MUON IDENTIFIER LEVEL-1 TRIGGER

• NIM Logic LVL-1 Trigger used during Run-2
• LVL-1 rejection is not required for AuAu until
  RHIC significantly exceeds design luminosity.
• LVL-1 rejection is required for lighter species,
  notably pp and dAu
• Used for stand-alone cosmic ray (diagnostic)
  trigger
• 4 gaps in trigger, each with 2 orientations.
  Trigger required hits in 6 out of 8
  gap/orientations per quadrant.
• 60 efficiency (largely due to HV issues
  expected to be improved for Run 3)

Use gaps 0,2,3,4. One MLU per quadrant.
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MUON LEVEL-2 TRIGGER

• A steerable roadfinding trigger using MuID input
• Available LVL-2 requirements
• minimum polar angle of muon(s) (12 or 15)
• opening angle between two muons
• centrality of event (measured by PHENIX)
• For Run-3 match to station 3 of the muon tracker
• For Run-3 require minimum invariant mass of
  dimuon pair!
• Efficient for muons from the vertex, good
  rejection of hadrons

Measured rejection factors
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EmCal based PID

• Now routinely usingTOF from EmCalto extend
  aperturefor our identified hadron analyses
• Already in use forHBT
• Will apply to f ? KK-

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TEC ? TRD upgrade

• Time Expansion Chamber ? Transition Radiation
  Detector
• TRD upgrades
• Install radiators
• Gas system
• Previous P-10
• TRD
• 50 Xe, 10-20 Methane40-30 He
• Recirculation
• General
• Previously 4 planes
• Now 6 planes
• End result
• Increased momentum resolution at high pT
• Increased electron ID capability at high pT

Electron Clusters
Drift Window
TR Photon
TRD Radiator
PUSH?
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South Muon Arm Improvementsand North Muon Arm
Commissioning

• South Arm
• Replacement of muon tracker Glink-Clink cables
• Muon tracker conformal coating added
• North Arm
• Installed!
• North muon tracker noise looks good
• General
• Replacement of faulty muon identifier HV
  connectors
• Muon identifier shielding
• Expect improved performance for next run

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d-Au Segment

• Assumptions
• Duration
• 2 weeks set-up
• 3 weeks commissioning
• 1 week studies (upper limit)
• 10 weeks data-taking
• Performance
• 4 nb-1 week delivered during data-taking period
• 20 cm rms vertex
• ds in blue ring
• Physics questions addressed
• Parton energy loss in cold nuclear matter
• J/Y production in nucleus over wide kinematic
  range
• Open charm production and propagation
• All the usual soft physics
• Dependence of above on number of participants
  (via gray tracks)

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TRIGGER RATE (Hz)
Background Studies
yellow target in

• Purpose
• To understand any issues with Au ions in either
  ring
• In preparation for anticipated high luminosity
  Au-Au in Run-4
• Needed due to
• Different optics in each ring
• Potential long lead time for any possible
  remedies
• Up to 1 week requested
• Results from Run-2 p-p run show benefit of
• Collimating halo
• Close collaboration with C-A D machine physicists

blue target in
collimate beam
collimate blue
collimator out
dump yellow
mis-steer
TIME
After ? 1 m achieved, significant
non-collision background observed. Studied
problem with help from RHIC during pp running by
mis-steering beam and seeing panel currents
remain high. Rates very sensitive to beam scrape.
Collimation helps tremendously. RHIC expects to
further investigate and improve this situation.
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Muon Identifier Shielding

• Prior preparation prevents previous poor
  performance

Ready for Run 3 now. Special thanks to Charlie
Pearson and C-A D.
Initial approach to shielding hand-stacked bars.

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Q. Why did we build RHIC?

• A To gain access to small cross-sections
  that are
• A) Fundamental
• B) Calculable
• C) Interesting
• which then allow us to use
• Ncoll ( aka binary or point-like)
• scaling of yields as our
• baseline hypothesis
• for probing a new state of matter
• (This of course one of many possible answers)

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An Example of Ncoll Scaling

• Q Are there rare probes at RHIC that scale as
  the number of binary collisions?
• A Yes, charm production (for Ncoll from 71 to
  975)

PHENIX Run-2 Preliminary Data presented at Quark
Matter 2002
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Run-2 High pT Results (Peripheral)

• PHENIX (Run-2) data on p0 production in
  peripheral collisions
• Excellent agreement between PHENIX measured
  p0s in p-pandPHENIX measured p0s in Au-Au
  peripheralcollisions scaled by the number of
  collisionsover 5 decades
• Demonstrates ability (and utility!) of measuring
  comparison data set in same detector to
  establish fundamental baseline for new
  effects in A-A collisions

PHENIX Preliminary
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Run-2 High pT Results (Central)

• Q Do all processes that should scale with Ncoll
  do just that?
• A No!
• ?Central collisions are different .
• This is a clear discoveryof new behavior at RHIC
• It is presumably a resultdue to formation of
  unusually denseand opaque matter earlyin the
  collision
• Intense theoretical activity to understand
  dependence on
• Medium properties(?)
• Deconfinement(??)

PHENIX Preliminary
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More (new) Run-2 results

• Observation of jet cones (near and away)
• Trigger on high pT p0
• Examine angular distribution wrt trigger
• Calibrate in p-p by comparison to PYTHIA
  predictions
• Apply to Au-Au
• Account for complicationsdue to flow in Au-Au
• (In progress)
• Systematize yields and shapes as a function of
  centrality
• Relate to suppression

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How to Calibrate the Suppression

• Attempt to separate effects from
• Initial state from final state scattering
• Cold vs hot nuclear matter
• via p-A (d-Au) collisions

B.Z. Kopeliovich et al., hep-ph/0201010
E. Wang and X.N. Wang, hep-ph/0202105
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Understanding the Suppression

• Q. Isnt the suppression just a measure of the
  (integrated) density?
• A. Perhaps, but
• Thats what wed like to determine via
  measurements in d-Au
• As such, it represents a qualitative advance
  towards understanding effective energy densities

R. Baier, PHENIX Collaboration Meeting, Jul-02
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Expected pT Range in d-Au

• C-A D optimistic guidance is 4 nb-1 / week
• Assume
• 50 vertex cut (conservative)
• 50 PHENIX efficiency (conservative)
• 10 weeks 10 nb-1 recorded
• Scale as 2 x 197 ? 4 pb-1 p-p equivalent
• This is x100 the sample in existing PHENIX p-p
  result
• pT range in excess of 15 GeV/c

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Yet more (new) Run-2 results

• First results on J/Y yields
• Measured in pp via
• ee- (central arms)
• mm- (South Muon arm)

s (pp-gtJ/Y) 3.8 0.6 (stat) 1.3 (sys) mb
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Yet more (new) Run-2 results

• And J/Y results for Au-Au
• Measured via ee- (central arms)
• And binned on centrality
• mm- datastill to come
• Clearlystatisticslimited( 24 mb-1
  versushoped-for300 mb-1)

Phys. Lett B 521 (2002) 195
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Charmonium Yields in d-Au

• Use measured PHENIX Preliminary p-p data as
  input to color evaporation model
• Reproduces
• xF dependence
• pT dependence
• Total cross section ( 4.0 mb versus quoted
  3.8 0.6 1.3 mb )
• Use this parameterization to compute expected
  yields in for 10 week d-Au run
• Results (next slides)

PHENIXPreliminary
PHENIXPreliminary
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J/Y Results in d-Au (I)

• Broad coverage in
• xF, pT and x2
• by combining
• North Arm
• Central Arm
• South Arm

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J/Y Results in d-Au (II)

• Excellent ability to measure Aa dependence versus
  various kinematic variables
• Again, broad coverage in
• xF, pT and x2
• by combining
• North Arm
• Central Arm
• South Arm

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Tagging with gray protons

• Tremendous utility of event characterization via
  gray protons shown in E910
• Will install refurbished E864 calorimeters inside
  ring to do same

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p?-p? Segment

• Assumptions
• Duration
• 2 weeks set-up
• 3 weeks commissioning
• 3 weeks data-taking
• Performance
• 2.8 pb-1 week delivered during data-taking period
• 20 cm rms vertex
• Polarization gt 40
• Longitudinal polarization at PHENIX IP
• Physics questions addressed
• Measurement of ALL via pion production
• Inclusive (comparison) measurements
• J/Y production
• Open charm production
• High pT hadron and photon production

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First Spin Physics (Run-2)

• New components
• Level-1 triggers
• EmCal
• Muon
• Spin-sorted scalers (4 x 120)
• Luminosity
• with
• polarization 25
• ? only very modest effective luminosity

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Projected Statistical Error from Run-2 AN
Measurement

• Even with this very modest start
• x 10 previous best (E704) measurement
• High pT at x0 permits pQCD treatment
• Should lead to bounds on the product
• (transversity quark distributions)
• x
• (Collins-Heppelman
• fragmentation function)

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Assumed Spin Developments

• Spin run is predicated on polarization in AGS
  40
• To be demonstrated during d-Au run
• (Soft limit)
• RHIC
• Achieve ltLgt 1031 cm-2 s-1
• Commission rotators
• Achieve down-ramp
• PHENIX
• Track spin-dependent (bunch-by-bunch) luminosity
• Extend triggers to accommodate x10 increase in
  luminosity
• Commission local polarimeter

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Projected Run-3 ALL Measurement

• Comparison of projected PHENIX ALL measurements
  (200 GeV, 3pb-1) with asymmetries predicted for
  two different assumed gluon polarizations

No detector changes required. Luminosity
requirements are consistent with C-A D
projections for luminosity. Theoretical
interpretation possible in pQCD as demonstrated
by comparison between measured PHENIX p0 cross
section and NLO pQCD. (next slide) Competes
with ongoing efforts at CERN (next slide).
W. Vogelsang
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RHIC Reduces Scale Dependence

• Already encountered this as part of our p-p
  comparison data
• Now note the direct relevance of this to
  understanding spin measurements at RHIC

PHENIXPreliminary
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PHENIX Beam Requirements for Spin Measurements

• Physics Goal Center
  of Mass Energy Polarization
  Luminosity
• Gluon polarization
• -Inclusive hadron production
  200 GeV 40
  3 pb-1
• -high x prompt photon production 200
  GeV 50
  320 pb-1
• -low x prompt photon production 500
  GeV 70
  800 pb-1
• Quark polarization
• (W-production)
  same
  run
• Transverse spin physics
• -Collins Heppelman FF
  200 GeV 50
  30 pb-1
• -Interference FF
  200 GeV
  70 300 pb-1
• Scheduling priorities a) Follow RHIC
  luminosity and polarization profile

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Impact of full PHENIX DG Measurement in Direct
Photon Production

• If the projected PHENIX Prompt Photon Data
  (200GeV, 320pb-1) are added to a global QCD
  analysis of existing DIS data

Present DIS
AAC Preliminary
M. Hirai, H.Kobayashi, M. Miyama et al. (The
Asymmetry Analysis Collaboration)
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Looking Ahead

• Run-4
• We must measure J/Y in Au-Au !
• (Run-3 d-Au request predicatedon commitment to
  such a runin Run-4)
• Run-5
• Fully operational muon arm new triggers
• Full exploration of J/Y productionversus
  Nbinary A(b)A(b) via
• Run-4 long run with Au-Au
• Run-5 light ion runs
• Spin
• Continued running to accumulate320 pb-1 at
  200 GeV

Log10(Nbinary)
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Run-2 Goals (previous PAC)

• Detector Commissioning of
• New sub-systems
• Integration of same into the detector
• Calibration of detector
• Trigger studies
• Experiment Complete what we started in Run-1
• Characterize properties of matter created in
  highest energy Au-Au collisions on all time
  scales
• All pT scales (as permitted by luminosity)
• Begin program of J/Y measurements
• (TBD) Obtain comparison data for same in p-p
  collisions
• (TBD) Begin spin program.
• Every expectation of a repeat performance for
  Run-3

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Re Npart scaling

• PHENIX has carefully studied both Ncoll and Npart
  scaling as a function of pT
• Clearly Npart is not the relevant scaling
  variable
• Reference nucl-ex/0207009