# Presentation: 641552

## 
PHENIX STATUS

W.A. Zajc
Columbia University
for the PHENIX Collaboration

**PHENIX STATUS**
**W.A. Zajc**
**Columbia University**
**for the PHENIX Collaboration**

## Outline	

- Collaboration Status
- Run-1 Accomplishments
- Papers to Date
- Fundamental Impact
- Run-2
- Goals
- Accomplishments
- Preliminary Data
- Spin Prospects
- Upgrades
- Conclusion

## What is PHENIX?

- Pioneering High Energy Nuclear Interaction eXperiment
- Goals:
-  Broadest possible study of A-A, p-A, p-p collisions to
- Study nuclear matter under extreme conditions
- Using a wide variety of probes sensitive to all timescales
- Study systematic variations with species and energy
- Measure spin structure of the nucleon
- These two programs have produced a detector with unparalleled capabilities

## The  Collaboration

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

## 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)

## PHENIX at RHIC

**3 global ****detectors**

## PHENIX Central 

**East Carriage**

**West Carriage**

**Ring Imaging Cerenkov**
**Drift Chamber**

**Beam-Beam Counter**

- PHENIX Central

## RHIC Runs

- RHIC runs to date
- Run-1, Summer 2000:
- Au+Au √sNN = 130 GeV, ~1 b-1
- Run-2, 2001-2:
- Au+Au √sNN = 200 GeV, ~ 24 b-1
-   p+p    √sNN = 200 GeV, ~0.13 pb-1, P ~ 25%
- Run-3, 2003:
- TBD
- TBD
- RHIC reviews to date
- Sep. 5-7, 2001
- Feb. 5-7, 2002
- Jul.31-Aug.2, 2002

## 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)

## From Run-1 to Run-2

- For 2001 Run:

- Run-1 (2000)

## Run-2 Improvements

- Essentially complete recovery of the “baseline” PHENIX detector
- PC2 and PC3 for West Arm
- Increase MVD coverage
- Remaining 4 sectors of EmCal electronics (RIKEN)
- Ersatz Level-1 EmCal trigger (RBRC)
- L1 RICH trigger, Data Collection Modules (US-J)
- Remaining 2 sectors of TEC electronics (UCR + DOE)
- Plus
- Installation of South Muon Magnet  + Tracker
- Plans for bandwidth recovery
- DCM’s: DOE Medium Energy
- EvB     : GSU
- Production of North Arm tracker mechanics
- Funding for North Arm tracker FEE   (new French collaborators)

## Run-2 DAQ and Trigger

- High bandwidth + physics triggers
- Able to use full luminosity of machine
- Implemented full set of Level-2 triggers
-  Single muon
-  J/ **** +-
-  J/ ****  e+e-
-  ****** **e+e-  peripheral (40-100%)
-  High pT
- Photon    (2.5-3.0 GeV/c cut)
- Electron (2.5 GeV/c cut)
- Charged (cut TBD)
-  e- coincidence
-  Coherent peripheral trigger
- DAQ Upgraded to
- ~30 Mb/s recording
- ~150 events/sec

## Run-3 and Beyond

## Run-1 Publications (1)

- “Centrality dependence of charged particle multiplicity in Au-Au collisions at sNN = 130 GeV”, _[PRL 86 (2001) 3500](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000086000016003500000001&idtype=cvips&gifs=yes)_
- “Measurement of the midrapidity transverse energy distribution from sNN = 130 GeV Au-Au collisions at RHIC”, _[PRL 87 (2001) 052301](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000087000005052301000001&idtype=cvips&gifs=yes)_
- “Suppression of hadrons with large transverse momentum in central Au-Au collisions at sNN = 130 GeV”, _[PRL 88, 022301 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000002022301000001&idtype=cvips&gifs=Yes)_.
- “Centrality dependence of +/-, K+/-, p and pbar production at RHIC,”_[PRL 88, 242301 (2002). ](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000024242301000001&idtype=cvips&gifs=yes)_
- “Transverse mass dependence of the two-pion correlation for Au+Au collisions at sNN = 130 GeV”, _[PRL 88, 192302 (2002) ](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000019192302000001&idtype=cvips&gifs=yes)_
- “Measurement of single electrons and implications for charm production in Au+Au collisions at sNN = 130 GeV”,_[PRL 88, 192303 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000019192303000001&idtype=cvips&gifs=yes)_

- 1st study of dN/d vs Npart

- 1st measurement of ET

- 1st measurement of high pT *suppression*

- 1st measurement of
- ‘high’ pT particle yields

- 1st measurement of open charm yields

- ‘1st’ measurement of source size at ‘high’ pT

## Run-1 Publications (2)

- Accepted for Publication:
- “Net charge fluctuations in Au+Au interactions at sNN = 130 GeV”,accepted for publication in  PRL,    _[preprint nucl-ex/0203014](http://xxx.lanl.gov/abs/nucl-ex/0203014)_
- “Event-by-event fluctuations in mean pT and mean ET in sNN = 130 GeV Au-Au collisions”, accepted for publication in Phys.  Rev. C, _[preprint nucl-ex/0203015](http://xxx.lanl.gov/abs/nucl-ex/0203015)_
- "Measurement of the lambda and lambda-bar particles in Au+Au Collisions at sqrt(s_NN)=130 GeV", accepted for publication in PRL,   _[preprint ](http://lanl.arxiv.org/abs/nucl-ex/?0204007)__[nucl](http://lanl.arxiv.org/abs/nucl-ex/?0204007)__[-ex 0204007"](http://lanl.arxiv.org/abs/nucl-ex/?0204007)_
- Submitted for Publication:
- “Flow measurements via two-particle angular correlations in Au+Au collisions at sNN = 130 GeV”, submitted to PRL,   _[preprint nucl-ex/0204005](http://xxx.lanl.gov/abs/nucl-ex/0204005)_
- “Centrality dependence of the high pT charged hadron suppression  in Au+Au collisions at sNN = 130 GeV”,submitted to PRL, _[preprint nucl-ex/0207009](http://xxx.lanl.gov/abs/nucl-ex?0207009)_
- In final preparation:
- “Particle ratios in Au+Au interactions at sNN = 130 GeV”
- “Systematics of hadron production in Au+Au interactions at  sNN = 130 GeV”

## Run-2 Goals(from Sep-01 Review)

- 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/ measurements
- Obtain comparison data for same in p-p collisions
- Begin spin program.

- 

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- 

- 

## Discovery at RHIC

- From Run-1:
- Persistence (growth!) of elliptic flow
- Rout  Rside
- Suppression                 at high pT
- Particle composition at high pT
- From Run-2 (already):
- All of the above
- J/
- Much more to come

## Luminosity

- Consider collision of ‘A’ ions per bunchwith                                 ‘B’ ions per bunch:

-                               A

-                               B

- Cross-sectional area ‘S’

## Change scale by ~ 109

- Consider collision of ‘A’ nucleons per nucleuswith                                 ‘B’ nucleons per nucleus:
- ‘Luminosity’

-                             A

-                               B

- Cross-sectional area ‘S’

*Provided:*
- No shadowing
- Small     cross-sections

## Rare Processes

- Particle production via *rare processes*  should scale with Ncoll , the number of underlying binary nucleon-nucleon collisions
- Roughly: Small    no shadowing  *per nucleon*  luminosity is relevant quantity
- Take scaling with Ncoll as our *null hypothesis*for hard processes

## 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...)

- }

## 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

## Another Example of Ncoll Scaling

- PHENIX (Run-2) data on 0 production in peripheral collisions:
- Excellent agreement between PHENIX measured 0’s in p-pandPHENIX measured 0’s in Au-Au  *peripheral*collisions scaled by the number of collisionsover ~ 5 decades

**PHENIX Preliminary**

## Extending Ncoll Scaling(?)

- 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**

## Is the suppression new?

- Yes- all previous measurements see *enhancement*, not *suppression*.
- This is qualitatively new physics made accessible by RHIC’s ability to produce
- (copious) perturbative probes
- (New states of matter?)
- Run-2 results show that this effect persists (increases) to the highest available transverse momenta

- Ncoll baseline

- ‘Understood’ enhancement from Cronin effect

**PHENIX Preliminary**

## More (new) Run-2 results

- Observation of jet cones (near and away)
*Trigger* on high pT 0
*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

## Yet more (new) Run-2 results

- First results on J/ yields
- Measured in pp via
- e+e- (central arms)
- +- (South Muon arm)

********** ****(pp->J/********) = 3.8 **_**+**_** 0.6 (stat) **_**+**_** 1.3 (sys) ********b**

## Yet more (new) Run-2 results

**Yet more (new) Run-2 results**

*And*  J/ results for Au-Au
- Measured via e+e- (central arms)
*And*  binned on centrality
- +- datastill to come
- Clearlystatisticslimited( 24 b-1    versushoped-for300  b-1)

**Phys. Lett B 521 (2002) 195**

## PHENIX at QM02 ≈ A Sample of ‘all’ Run-2 results

| Correlations and fluctuations |  |  |
| --- | --- | --- |
| Parallel 18/07 | A. Enokizono | Two-particle correlations measured by PHENIX at sqrt(s_NN)=200GeV in Au-Au collisions |
| Parallel 18/07 | S. Esumi | Identified and charged particle azimuthal anisotropy in PHENIX at RHIC |
| Parallel 18/07 | J. Nystrand | Charge Fluctuations at Mid-Rapidity in Au+Au Collisions in the PHENIX experiment at RHIC |
| Particle Yields |  |  |
| Parallel 18/07 | A. Bazilevsky | Charged Particle Multiplicity and Transverse Energy Measurements in Au-Au collisions in PHENIX at RHIC |
| Parallel 18/07 | D. Mukhopadhyay | Phi meson production in Au-Au collisions at s_{NN} = 200 GeV |
| Parallel 18/07 | J. Burward-Hoy | Source parameters from identified hadron spectra and HBT radii for Au-Au collisions in PHENIX |
| Plenary 20/07 | Tatsuya Chujo | Results on Particle Yields from the PHENIX Experiment at RHIC |
| High transverse momentum |  |  |
| Parallel 20/07 | D. D'Enterria | High Pt neutral pion suppression in Au+Au collisions. Results at $\sqrt{s_{NN}$ = 200 GeV |
| Parallel 20/07 | H. Torii | Measurement of the 0 cross section in proton-proton collisions at √s =200 GeV with PHENIX |
| Parallel 20/07 | T. Sakaguchi | High $p_{T}$ identified hadron ratios in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions |
| Parallel 20/07 | M. Chiu | Charged/neutral Correlations from a Trigger Gamma |
| Parallel 20/07 | J. Jia | High momentum charged hadron spectra from Au-Au collisions at RHIC |
| Parallel 20/07 | N.N. Ajitanand | Two-particle Azimuthal Correlation Functions in PHENIX |
| Plenary 22/07 | Saskia Mioduszewski | High Pt results from Phenix |
| Leptons and photons |  |  |
| Parallel 22/07 | K. Reygers | Results on Photon Production in Au+Au collisions at RHIC |
| Parallel 22/07 | R. Averbeck | Single inclusive leptons from heavy flavor decays at RHIC |
| Parallel 22/07 | A. Frawley | J/\Psi  ee$ and $J/\Psi  mu mu Measurements in Au-Au and p-p Collisions at √s = 200 AGeV |
| Plenary 23/07 | Jamie Nagle | Leptons and Photons in PHENIX |

## Runs 3, 4 and 5: 
(Subject to the usual caveats about surprises and flexibility):
Heavy Ions
Fully operational muon arms+ new triggers
Full exploration of J/ productionversus “Nbinary” ~ A(b)*A(b) via
A long run with Au-Au
A series of shorter light ion runs
d-A running as baseline for 
High pT suppression in coldnuclear matter
J/ suppression 
Strangeness enhancements
Spin
    First run with spin rotators
Start of ALL physics
N.B.: RHIC must deal with a scheduling problem unprecedentedin collider history

- (Subject to the usual caveats about surprises and flexibility):
- Heavy Ions
- Fully operational muon arms+ new triggers
- Full exploration of J/ productionversus “Nbinary” ~ A(b)*A(b) via
- A long run with Au-Au
- A series of shorter light ion runs
- d-A running as baseline for
- High pT suppression in coldnuclear matter
- J/ suppression
- Strangeness enhancements
- Spin
-     First run with spin rotators
- Start of ALL physics
- N.B.: *RHIC must deal with a **scheduling problem **unprecedented**in collider history*

- 

**Looking Ahead**

## Spin in PHENIX

- An integral part of our collaboration
- ~11 of 57 institutions
- An integral part of our detector
- South Muon Arm, high pT triggers, ...
- An integral part of our run plan
- Commitment to significant allocation of running ~each RHIC year
- Run-3 Run Coordinator (M. Gross Perdekamp)
- An integral part of our physics
- Confinement  mixing of helicity components

**Bag****Wall**

## Goals of the Spin Program

- Determine the complete spin structure of the nucleon
- In particular, contributions from
- Gluon polarization  (G)
- Sea-quark polarization (******u , ********d** )
- Why RHIC?
- High energy  factorization
- Polarized hadrons  gq, gg collisions
- High energy  new probes (W’s)

## 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

## 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

## Projected Statistical Error from Run-2 AN Measurement

**Projected Statistical Error from Run-2 A****N**** Measurement**

- Even with this very modest start
- ~ x 10 previous best (E704) measurement
- High pT at x=0 permits pQCD treatment
- Should lead to bounds on the product
- (transversity quark distributions)
- x
- (Collins-Heppelman
-  fragmentation function)

## PHENIX Beam Requirements* for Spin Measurements

- 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
-                                                b) Competing programs at CERN  and DESY.                                            (COMPASS has started production running in July 2002!)
- Note the requirement for ~103 (~104) improvement in P2L  (P4L)

**PHENIX Beam Requirements* ****for Spin Measurements**

## Impact of Projected Run-3 PHENIX ALL Measurement

**Impact of Projected Run-3 ****PHENIX A****LL**** Measurement**

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

- W. Vogelsang

- Theoretical interpretation possible in pQCD as demonstrated by comparison between measured PHENIX π0   cross section and NLO pQCD.
- No detector changes required.
- Luminosity requirements are consistent with CAD projections for luminosity.
- Competes with ongoing efforts at CERN.

## Impact of full PHENIX G Measurement in Direct Photon Production

**Impact of full PHENIX *********G***** 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:

**AAC Preliminary**

- M. Hirai, H.Kobayashi, M. Miyama *et al. (The Asymmetry Analysis Collaboration)*

- Present DIS

## Projected Impact of PHENIX 500 GeV Spin Measurement for Quark Polarization 

- Projected results on quark and anti-quark distributions for 800 pb-1 . Unique capability at RHIC in W-production.
- Flavor decomposition will reduce the uncertainty in current pol-PDF models.
- Requires increased selectivity of the muon trigger (rejection = 50 x present value)

**Projected Impact of PHENIX 500 GeV ****Spin Measurement for Quark Polarization**** **

- J. Soffer and N. Saito

## PHENIX and RHIC II

- PHENIX is the “upgrade-ready” detector:
- Extensive set of *working*
- Level-1 triggers (mostly for p-p)
- Level-2 triggers (mostly for A-A)
- Flexible, modular DAQ with clear upgrade path
- Demonstrated high pT and/or high mass capabilities
- “Reserved” real-estate for future sub-systems
- Active working groups andadvanced planning  for upgrades

## New Physics to be Addressed with an Upgraded PHENIX Detector

- Low mass dilepton pairs
-  Improved measurements of heavy flavor (c,b) production
-  Jet studies and -jet correlations
-  High pT identified particles
-  Truly rare processes
- Inclusive particle spectra and direct photons out to high pT
-  Drell-Yan continuum above the J/
-  Upsilon spectroscopy - (1S),(2S),(3S)
-  W-production

## PHENIX Upgrade Topics

**PHENIX Upgrade Topics**

- Heavy Ion Physics
- Shift of focus from establishing the existence of QGP and first studies of its properties to systematic study of QCD at high T
- Focus on key measurements only partially addressed by original PHENIX setup:
- upsilon spectroscopy, Y(1S), Y(2S), and Y(S3)
- lepton pair continuum:      low mass to Drell-Yan
- heavy flavor
- high pT phenomena
**Spin Physics  **
**gluon spin structure over large x range **
**heavy flavor**
**W-Boson**
**transversity**
**p-A Physics **
**parton structure of nuclei**
**diffractive processes**

## PHENIX Detector Upgrades

**PHENIX Detector Upgrades**

- central vertex spectrometer
- flexible magnetic field
- multi layer silicon vertex tracker
- TPC/HBD (Hadron Blind Detector)
- forward vertex tracking
- multiple layer silicon
- enhanced particle ID
- TRD (east)
- Aerogel/TOF (west)
- enhanced muon trigger
- forward hodoscopes
- forward calorimeter
- station 1 anode readout
- pA trigger detectors
- DAQ

**Vertex Spectrometer**

- 

- 

- 

## TPC/HBD Schematic Design

- Drift regions

- HV plane (~ -30kV)

- TPC Readout Plane
- ~50000 channels

- Readout Pads
- R ~ 1 cm
-   r ~ 2 mm

- CsI  Readout Plane
- 5000-10000 channels

- GEM

**TPC/HBD Schematic Design**

- CF4 or CH4	drift gas
- 		radiator gas
- 		detector gas

- High rate capability: drift-time ~ 4 s

- Need to develop integrated electronics

## Physics Gains from TPC/HBD

- HBD: Huge improvement in ability to reject combinatoric background
- Greatly increased sensitivity to
- ()  e+e-
- Continuum di-lepton pairs
- TPC: 2 coverage at small radius
- Greatly improved background rejection
- Increased ability to detect weak decays
- Increased capabilities in jet+jet and photon+jet physics

## Proposed Silicon Tracker

**Pixel barrels **** (50 ********m x 425 ********m)**
**Strip barrels**** (80 ********m x 3 cm)**
**Pixel disks  (50 ********m x 200 ********m)**

**1.0% X****0 ****per layer**

- 500 mm Be Beam Pipe

- 1.2<||<2.4

- ||<1.2

**Proposed Silicon Tracker**

## Enhanced Physics with a High Precision Vertex and Tracking Detector

- Separation of charm and bottom decays through inclusive electrons (Central Arm)
-   improve measurement accuracy of c and b cross sections to ~ 10%
-   separate c and b in each pT bin => flavor dependence of QCD energy loss
-  Direct measurement of D mesons
-   combined with particle ID, can measure D -> K modes
-    pT spectrum of D’s, flavor dependence of QCD energy loss
-  Open heavy flavor (Muon Arms)
- D-> X, B -> J/ -> +-
-  Improved momentum resolution for Upsilon spectroscopy
-  Enhanced capabilities for spin physics
- wider acceptance (g-jet & jet-jet studies, transversity), b-tagging
-  Enhanced physics capabilities for charm and bottom in pA

## Extended PID with Aerogel

**Aerogel together with TOF can extend the PID capability up to 10 GeV/c**

- Y. Miake

## Aerogel +TOF

**Aerogel +TOF**

**Coverage of 4 TOF panels**
**Since no space on the East, install on the West.**
**Remove 2 lower TOF panels from East after pp run**
**1 spare panel**
**1 panel to be constructed**

**BELLE Aerogel Module**

## Enhanced Muon Trigger

- Nosecone calorimeter -> dA (centrality, low x),
-                                         W-tag, NTC’, b-tag
-  mu Tr anodes             -> reconstruction in AA
-                                     -> high mass di-lepton trigger
-                                          for AA
- hodoscope+Cerenkov -> Beam gas rejection?

- Separate muons from Hadron decays
- from muons from W-production by
-    a) momentum cuts
-    b) event topology

**Enhanced Muon Trigger**

- Required in order to avoid pre-scalingsingle-muon Level-1 trigger,
- thereby preserving bandwidth for
-   (very rare) W’s

## Time Scale and Cost

**   ****Install North Muon Spectrometer**
**   ****Upgrade TEC to TRD**
**2002-2004**
**  ****Silicon strip detectors**
**  ****Prototype silicon pixel detector**
**  ****Prototype HBD (upgradable to TPC)**
**  ****Prototype aerogel detector**
**2005-2007**
** ****Complete silicon pixel detectors**
** ****Complete TPC/HBD **
** ****Complete aerogel detector**

**R&D 2002-2005**
**  ****presently supported by various**
**   ****institutional funds (LDRDs,RIKEN)**
**  ****requires ~ $3-4M over 3-4 yrs**
**  ****needs DOE funding to continue**
**Construction 2004-2007**
** ****Staged approach, with detectors**
**  ****requiring less R&D to be**
**  ****implemented first**
** ****Rough estimate of detector **
**  ****construction costs ~ $30-40M**
** ****NSAC plan shows $80M in RHIC II**
**  ****detector upgrades over 7 years**
**  ****starting in FY05 **

**Time Scale and Cost**

## Agenda for Next PHENIX Upgrades Meeting, Aug.5-6

## Upgrade Summary

- The physics addressed is a qualitative addition to the PHENIX (and RHIC) program
- low mass e-pairs
-  enhanced production or medium effects, mee < m
-  thermal radiation, m<mee < m J/
- open charm, B, W production
- high pT leptons, precision vertexing
- extended direct photon, jet capability
-  single  spectra down to pT < 1 GeV/c
-  , 0 (/jet) up to pT >> 20 GeV/c
- increased charged particle tracking acceptance
- low-x coverage for QCD in pA
- Some detector choices could provide enhanced capability of more than one kind (e.g., inner tracker)  design optimization
- Some technologies need further development (e.g., HBD)  R&D program (ongoing)
- The open geometry of PHENIX makes these and other upgrade paths possible.

## Outline	(and Summary)

- Collaboration Status
- Run-1 Accomplishments
- Papers to Date
- Fundamental Impact
- Run-2
- Goals
- Accomplishments
- Preliminary Data
- Spin Prospects
- Upgrades
- Conclusion

- Healthy, growing

- Manifold

- Many, substantial

- Yes!

- Achieved

- Already exciting

- In hand, impressive

- Superb

- Well-planned, exciting

- Further reviews not needed at this time

## 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