# Presentation: 940042

**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/RBUP03/PacSep03.pdf****  )**

- 29-Sep-03

## The  Collaboration

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

- 29-Sep-03

## Beam Use Proposal

**Requested input:**
**Desired “beam run segments”**
**Physics from same**
**Investigate “27” and “37” week scenarios**
**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” ******** 2003 run d+Au/p+p at 200 GeV**

- 29-Sep-03

## 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)**

- 29-Sep-03

## Run-1 Publications 

**“****Centrality dependence of charged particle multiplicity in Au-Au collisions at ********s****NN**** = 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 ********s****NN**** = 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 ********s****NN**** = 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 ********s****NN**** = 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 ********s****NN**** = 130 GeV”,**_**[PRL 88, 192303 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000019192303000001&idtype=cvips&gifs=yes)**_**"Net Charge Fluctuations in Au+Au Interactions at ********s****NN**** = 130 GeV,"  **_**[PRL. 89, 082301 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000089000008082301000001&idtype=cvips&gifs=Yes)**__** **_
**"Event-by event fluctuations in Mean p_T and mean e_T in sqrt(s_NN) = 130GeV Au+Au Collisions"  **_**[Phys. Rev. C66, 024901 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000066000002024901000001&idtype=cvips&gifs=yes)**__** **_
**"Flow Measurements via Two-particle Azimuthal Correlations in Au + Au Collisions at ********s****NN**** = 130 GeV" , **_**[PRL 89, 212301 (2002)](http://link.aps.org/abstract/PRL/v89/e212301)**_** **** **
**"Measurement of the lambda and lambda^bar particles in Au+Au Collisions at ********s****NN**** =130 GeV", **_**[PRL 89, 092302 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000089000009092302000001&idtype=cvips&gifs=Yes)**_** **
**"Centrality Dependence of the High pT Charged Hadron Suppression in Au+Au collisions at ********s****NN**** = 130 GeV", **_**[Phys. ](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-4899P6C-B&_coverDate=05/22/2003&_alid=115796574&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5539&_sort=d&view=c&_acct=C000002018&_version=1&_urlVersion=0&_userid=18704&md5=ab64ecd5f8cfe42c881e0c)**__**[Lett](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-4899P6C-B&_coverDate=05/22/2003&_alid=115796574&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5539&_sort=d&view=c&_acct=C000002018&_version=1&_urlVersion=0&_userid=18704&md5=ab64ecd5f8cfe42c881e0c)**__**[.  B561, 82 (2003)](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-4899P6C-B&_coverDate=05/22/2003&_alid=115796574&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5539&_sort=d&view=c&_acct=C000002018&_version=1&_urlVersion=0&_userid=18704&md5=ab64ecd5f8cfe42c881e0c)**_** **
**"Single Identified Hadron Spectra from ********s****NN**** = 130 GeV Au+Au Collisions",  to appear in Physical Review C,****  **_**[nucl-ex/0307010](http://xxx.lanl.gov/nucl-ex/0307010)**_** **** **

- 29-Sep-03

## Our latest Run-1 Publication

**"Single Identified Hadron Spectra from ********s****NN**** = 130 GeV ****Au+Au Collisions", ****to appear in  ****Physical Review C **_**[nucl-ex/0307010](http://xxx.lanl.gov/nucl-ex/0307010)**__** **__** **_
**An “archival” ****publication detailing ****our entire analysis****methodology for ****identified particles**
**37 pages**
**3 appendices**
**28 figures**
**16 tables**

- 29-Sep-03

## From Run-1 to Run-2

**For 2001 Run:**

- Run-1 (2000)

- 29-Sep-03

## Run-2 Publications 

**"Suppressed ********0**** Production at Large Transverse Momentum in Central Au+Au Collisions at ********s****NN**** = 200 GeV" , **_**[PRL 91, 072301 (2003) ](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000091000007072301000001&idtype=cvips&gifs=yes)**__** **_
**"Scaling Properties of Proton and Anti-proton Production in ********s****NN**** = 200 GeV Au+Au Collisions“, accepted for publication in PRL 21 August 2003, **_**[nucl-ex/0305036](http://xxx.lanl.gov/nucl-ex/0305036)**_** **** **
**"J/Psi Production in Au-Au Collisions at ********s****NN**** =200 GeV at the Relativistic Heavy Ion Collider", accepted for publication in Phys. Rev. C on 6 September 2003, **_**[nucl-ex/0305030](http://xxx.lanl.gov/nucl-ex/0305030)**_** **** **
**"Elliptic Flow of Identified Hadrons in Au+Au Collisions at ********s****NN**** = 200 GeV" , accepted for publication in PRL 9 September 2003, **_**[nucl-ex/0305013](http://xxx.lanl.gov/nucl-ex/0305013)**_** **** **
**"Midrapidity Neutral Pion Production in Proton-Proton Collisions at ********s = 200 GeV“, accepted for publication in PRL on 19 September 2003, **_**[hep-ex/0304038](http://arxiv.org/abs/hep-ex/0304038)**_** **
**"Identified Charged Particle Spectra and Yields in Au-Au Collisions at ********s****NN**** = 200 GeV" , accepted for publication in Physical Review C on 23 Sep 2003, **_**[nucl-ex/0307022](http://xxx.lanl.gov/nucl-ex/0307022)**_** **
**"J/psi production from proton-proton collisions at ********s = 200 GeV“, submitted to PRL July 8 2003, **_**[hep-ex/0307019](http://xxx.lanl.gov/hep-ex/0307019)**_** **
**"High-pt Charged Hadron Suppression in Au+Au Collisions at ********s****NN**** = 200 Gev”, submitted to Physical Review C on 11 August 2003, **_**[nucl-ex/0308006](http://xxx.lanl.gov/nucl-ex/0308006)**_** **

- 29-Sep-03

**Notes:**
BRAHMS Collaboration (I. Arsene et al.)" Transverse Momentum Spectra in Au+Au and d+Au collisions at sqrt(s_NN)=200 GeV and the Pseudorapidity Dependence of High pt SuppressionPhys. Rev. Lett 91, 072305 (2003)

BRAHMS Collaboration"Rapidity dependence of Charged Anti-particle-to-Particle ratios in Au+Au Collisions at sqrt(s_NN) = 200 GeV"Phys. Rev. Lett. 90,102301 Mar. 2003.2002

  BRAHMS Collaboration"Pseudorapidity distributions of charged particles from Au+Au collisions at the maximum RHIC energy"Phys. Rev. Lett. 88, 202301(2002)

ρ0 Production and Possible Modification in Au+Au and p+p Collisions at sqrt(snn) = 200 GeV J. Adams et al, submitted to Phys. Rev. Lett. July 30, 2003. [nucl-ex/0307023](PS| PDF) 

Particle dependence of azimuthal anisotropy and nuclear modification of particle production at moderate pT in Au+Au collisions at sqrt(snn) = 200 GeVJ. Adams et al, submitted to Phys. Rev. Lett. [nucl-ex/0306007] PDF) 

Transverse momentum and collision energy dependence of high pT hadron suppression in Au+Au collisions at ultrarelativistic energiesJ. Adams et al, submitted to Phys. Rev. Lett. [nucl-ex/0305015]. PDF) 

Disappearance of back-to-back high pT hadron correlations in central Au + Au collisions at sqrt(snn) = 200 GeVC. Adler et al. Phys. Rev. Lett. 90, 082302 (2003)(PS PDF) as published: 28 February 2003 

Centrality dependence of charged antiparticle to particle ratios near mid-rapidity in d+Au collisions at sqrt(s_NN)=200 GeVSubmitted to Phys. Rev. C Rapid Comm.     Links: Local, LANL, Figures, and Data 

Charged hadron transverse momentum distributions in Au+Au collisions at sqrt(s_NN) = 200 GeVSubmitted to Phys. Lett.B             Links: Local, LANL, Figures, and Data 

Comparison of the Total Charged-Particle Multiplicity in High-Energy Heavy Ion Collisions with e+e- and pp/pbar-p DatasSubmitted to Phys. Rev. Lett.       Links: Local, LANL, Figures, and Data 

Significance of the fragmentation region in ultrarelativistic heavy ion collisionsPhys. Rev. Lett. 91, 052303 (2003).           Links: Local, LANL, Figures, and Data 

Ratios of charged antiparticles to particles near mid-rapidity in Au+Au collisions at sqrt(sNN)=200 GeVPhys. Rev. C 67, 021901R (2003)                   Links: Local, LANL, Figures, and Data 

Centrality Dependence of the Charged Particle Multiplicity near Mid-Rapidity in  Au+Au Collisions at sqrt(sNN)=130 and 200 GeV Phys. Rev. C65, 061901R (2002).                  Links: Local, LANL, Figures, and Data 

## Our First p+p Publication

**"Midrapidity Neutral Pion Production in Proton-Proton Collisions at ********s = 200 GeV“, accepted for publication ****in PRL on 19 September 2003, hep-ex/0304038 **
**Important confirmation of ****of theoretical foundations for spin program**
**Results consistent with pQCD calculation**
**Favors a larger gluon-to-pion FF (KKP)**
**Run3 results reproduce Run2 results**
**Confirm the Run-3 data reliability and consistency**
**Run3 data reaches even higher p****T****’s;**** results will be finalized soon**

- 29-Sep-03

## One archival Run-2 Publication

**"Identified Charged Particle Spectra and Yields in Au-Au Collisions at ********s****NN**** = 200 GeV" , accepted for publication in ****Physical Review C ****on 23 Sep 2003, ****nucl-ex/0307022 **
**An “archival” ****publication extending ****our identified particles analysis methodology to Run-2**
**37 pages**
**24 figures**
**29 tables**

- 29-Sep-03

## Run-3 and Beyond

- 29-Sep-03

##       Run-3: Design Configuration!

**Central Arm Tracking**
-       Drift Chamber
-       Pad Chambers
-       Time Expansion Chamber
**Muon Arm Tracking**
-       Muon Tracker:  **North Muon Tracker**
**Calorimetry**
-       PbGl
-       PbSc
**Particle Id**
-       Muon Identifier: **North Muon Identifier**
-       RICH
-       TOF
-       TEC
**Global Detectors**
-       BBC
-       ZDC/SMD  **Local Polarimeter**
**      ****Forward Hadron Calorimeters**
-       NTC
-       MVD
**Online Calibration and Production**

- 29-Sep-03

## Run-3 Publications 

**"Absence of Suppression in Particle Production at Large Transverse Momentum in ********s****NN**** = 200 GeV d+Au Collisions”, ****PRL 91, 072303 (2003) **
**PID-ed particles (********0****’s) out to the highest p****T****’s PHENIX’s unique contribution to the June “press event”**

- 29-Sep-03

## Publication Summary

**Run-1**
**12 publications**
**First 5 are “TopCites”**
**One “archival” summary**
**Run-2**
**8 submissions to date**
**6 accepted/published**
**Several more still in progress**
**One “archival” summary**
**Run-3**
**One publication**
**Many to follow**

- 29-Sep-03

## Forthcoming Run-3 Results

**Centrality selected**
**Charged hadrons**
**Identified charged hadrons**
******0****’s**
**Opposite centrality evolution of Au+Au compared to d+Au control.**

**Au + Au **

**d + Au Control**

- Preliminary Data

- Final Data

- PHENIX Preliminary

- 29-Sep-03

## Run-3 J/’s

**d+Au**
**p+p**

**SOUTH ARM**

**NORTH ARM**

- 29-Sep-03

## Rotators at IP8 commissioned via local polarimeters
Forward neutron transverse asymmetry (AN) measurements
SMD (position) + ZDC (energy)

Then longitudinally polarized protons used to obtain first glimpse of ALL(0)

**Rotators at IP8 commissioned via local polarimeters**
- Forward neutron transverse asymmetry (AN) measurements
- SMD (position) + ZDC (energy)
- Then longitudinally polarized protons used to obtain first glimpse of **A****LL****(********0****)**

**Run-3 Spin Results**

- SMD

- ZDC

- Vertical   ~ ±/2
- Radial    ~ 0
- Longitudinal  no asymmetry

- distribution

- 29-Sep-03

## Local Polarimeter at PHENIX

- Spin Rotators OFF

**Blue**

**Yellow**

- Spin Rotators ON, Current Reversed

**Yellow**

**Blue**

**Blue**

**Blue**

**Yellow**

**Yellow**

- Spin Rotators ON, Almost...

- Spin Rotators ON, Correct!

- |P|=30%, PT=0%  PL=30%)

- |P|=37%, PT=24% PL=28%)

- PB=35.5%

- PB=37%

**Run-3**

**Essential to success of Run-3 spin physics!**

- 29-Sep-03

**Notes:**
SAVED OUR SPIN RUN!!!

## First Results on ALL

**First Results on A****LL**

**Presented this month at Dubna spin conference**
**Extensive (ongoing)****study of systematics**
**Bunch shuffling,****background studies,****A****L**** checks, ...**
**Relative luminosity****precision ~ 2.5 x 10****-4**** **
**Contribution to ****A****LL****  < 0.2%**
**Dominated by statistical****errors from 0.22 pb****-1**** sample**
**A very important ****proof-of-principle****for spin program!**

- Calculations: B.Jäger *et al*., PRD67, 054005 (2003)

- 29-Sep-03

## Run-4 Additions

**Rφ**

**Z**

**160 Cells : 16 x 10**

**Aerogel Cell**
**(11x22x11 cm****3****)**

**PMT’s**

**Aluminum Box**

**Aerogel Array**

**Aerogel in here**

**Light Mixer**

**The Aerogel detector is a threshold Cerenkov counter**
**Aerogel is a very low density, SiO****2**** – based solid**
**Aerogel has index of refr. between gases & liquids. **
**Ident. charged particles in a range inaccessible with other  technologies. **

**Run-4 Additions**

- 29-Sep-03

## Extended PID with Aerogel

**Aerogel together with TOF can extend the PID capability up to 10 GeV/c**
**(Without TOF, no K-proton separation at < 5 GeV/c)**** **

- Y. Miake

- 29-Sep-03

## Physics Motivations

**Strong motivation given**
**Jet Quenching!?**
**Predictions of quark recombination models (and their provocative conclusions)**

**Peripheral**

**Central**

**Run-4 request should extend results for PID-ed K’s and p’s into the 5-7 GeV/c range**

- 29-Sep-03

##       PHENIX: Run History

**Run-1**

**Run-2**

**Run-3**

- 29-Sep-03

## Run Request Summary

**Au+Au at 200 GeV, ****with goal of developing highest possible integrated luminosity**
**An aggressive program of luminosity and polarization development for p+p, ****with the goal of the earliest practicable measurement of ********G**
**Light-ion running, ****to investigate dependence on system size**
**A reduced energy run, ****again with emphasis on obtaining highest possible integrated luminosity**
**High integrated luminosities achieved via minimal variations in species and energies, ****as per CAD guidance**

- 29-Sep-03

## The Run Plan At A Glance

**An quantitative, integrated, planning exercise:**
**Quantitative:**
**Direct implementation of CAD guidance**
**Yield estimates (whenever possible) based on existing PHENIX measurements and known scaling laws**
**Integrated: ****Sequential set of measurements designed to deliver comparable sensitivities in ~ all channels**
**Planning: ****Based on *****current***** knowledge of machine, detector, physics and future developments**

- 29-Sep-03

## Note on Methodology

**CAD guidance, “linear growth model” implemented in spreadsheet**
**Physics yields for representative measurements *****calibrated***** based on PHENIX *****measurements***
**Extensive “phase space” of options explored in the planning process**
**Were led back to a position consistent with our previous multi-year proposals to PAC**
**Exploits the *****demonstrated***** capabilities of PHENIX to use the full luminosity of RHIC to measure identified particles to the highest possible transverse momenta**

-  ~ 211 J/’s
- 3.11 ± .02 GeV
-  = 143 ± 14 MeV

**opposite-sign pairs**
**same-sign pair bkgd**

******0****’s**

- 29-Sep-03

## Compare to Conceptual Design Report (29-Jan-93)

**Conclusions:**
**~All goals accomplished **
***As permitted by available integrated luminosity***
**For Au-Au (d-Au) only**
**Much remains **
**Truly rare probes in Au-Au**
**Species scans **
**Energy variation**

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- 29-Sep-03

**Notes:**
T = L*dt / L 
   = (24 /microbarns) / (2 x E26 /cm^2/s )
   = 24 E30 / 2 E26 sec
    = 12 E4 sec
    = 12 E4 sec / 3.6E3 sec/hr
    = 33 hours (!)

## Perspective

**The machine achievements in the first 3 years of RHIC operations have been ***spectacular ***:**
**3 different colliding species (Au-Au, p-p, d-Au)**
**3.5 energies for Au-Au (19, 56, 130, 200) GeV**
**First ever polarized hadron collider**
**Design luminosity for Au-Au**
**(Etc.)**
**Physics has been produced at “all” cross-sections:**
**Heavy Ions**
**barn:   dN****ch****/d******** vs N****part     **_**[PRL 86, 3500 (2001)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000086000016003500000001&idtype=cvips&gifs=yes)**_** **
**mb   :  v****2****(p****T****)                      **_**[nucl-ex/0305013](http://xxx.lanl.gov/nucl-ex/0305013)**_**  **           (to appear in PRL)
******b    :  R****AA****(p****T****)                   **_**[PRL 88, 022301 (2002)](http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000088000002022301000001&idtype=cvips&gifs=Yes)**_
**nb    :  J/******** (limit)               **_**[nucl-ex/0305030](http://xxx.lanl.gov/nucl-ex/0305030)**_**              (to appear in PRC)**
**Spin**
**Life (for A****LL****) begins at ~inverse pb**
**A start from Run-3? (0.35 pb****-1****)**
**Future output of the program **
**Depends ***crucially*** on developing large integrated luminosities**
**Adversely affected by original 37 weeks ******** 27 weeks per year**
**Enhanced by proposed program of upgrades**

- Spectacular

- 29-Sep-03

## Run-4

**27 weeks**
**Au+Au 200 GeV**
**5+14 weeks**
**Many rare channels**
**p+p 200 GeV**
**5+0 weeks**
**Beam development**
**37 weeks**
**Au+Au 200 GeV**
**5+19 weeks**
**Many rare channels**
**p+p 200 GeV**
**5+5 weeks**
**Beam development**
**A****LL****(********0****)**

- 29-Sep-03

## Run-4 Luminosity (J/)

**A quest to develop *****highest possible integrated luminosity***** in full energy Au+Au running**
**To eliminate statistical ambiguity in many production channels**
**Example: J/******** production**
**27 week scenario:**
**2.6******** (e****+****e****-****)**
**3.2******** (********+********-****)**
**(in 0-20% centrality bin)**

- 29-Sep-03

## Run-4 Luminosity (  e+e-)

**A quest to develop *****highest possible integrated luminosity***** in full energy Au+Au running**
**To eliminate statistical ambiguity in many production channels**
**Example: ********→ e****+****e****-**
**Run-2**
**Run-4**
**x10-15 yield**
**Improved S/B**

- PHENIX Preliminary

- 29-Sep-03

## Run-4 Luminosity (Direct Photons)

**A quest to develop *****highest possible integrated luminosity***** in full energy Au+Au running**
**To eliminate statistical ambiguity in many production channels**
**Example: Direct photons**
**Run-2**
**Statistics limited at ****~4 GeV/c**
**Run-4**
**Extend this to ****~10 GeV/c**

**HIGH-ENERGY PHOTONS FROM PASSAGE OF JETS THROUGH QUARK GLUON PLASMA.****by R. J. Fries, B. Muller and ****D. K. Srivastava, Phys.Rev.Lett.90:132301,2003**** **

- 29-Sep-03

## Run-4 Luminosity (Other Examples)

**Run-4 Luminosity (Other Examples)**

**A quest to develop *****highest possible integrated luminosity***** in full energy Au+Au running**
**To eliminate statistical ambiguity in many production channels**
**Other examples: **
**Low-mass pairs**
**Charm flow**
**“****Jet” correlations**

**Inclusive electrons/positron v****2**

- 29-Sep-03

## Recombination Tested

**The *****complicated***** observed flow pattern in ****v****2****(p****T****)**** ****d****2****n/dp****T****d******** ~ 1 + 2 ****v****2****(p****T****) ****cos (2 ********)**
**is predicted to be *****simple***** at the quark level under**** ****p****T**** → p****T ****/ n , v****2**** → v****2**** / n ,   n = 2,3 for meson,baryon**
_***if***_** the flow pattern is established at the quark level**

**Compilation courtesy of H. Huang**

- 29-Sep-03

## Yet Another Luminosity Limited Observable

**New PHENIX Run-2  result on v2 of ********0****’s:**
**Clearly would****benefit ****from Run-4 statistics**

- PHENIX Preliminary

- 29-Sep-03

## Run-5

**27 weeks**
**Si+Si 200 GeV**
**5+9 weeks**
**Many rare channels**
**p+p 200 GeV**
**5+5 weeks**
**A****LL****(********0****)**
**37 weeks**
**Si+Si 200 GeV**
**5+14 weeks**
**Many rare channels**
**p+p 200 GeV**
**5+10 weeks**
**Beam development**
**Quality A****LL****(********0****)**

- 29-Sep-03

## To Fe or not to Fe?

**0-th order:**
**We desire the species that will lead to highest possible integrated (parton-parton) luminosities**
**CAD guidance neutral in this respect ****(but perhaps Si set-up is easier?)**
**1****st****-order:**
**Clearly depends on assumptions regarding (length, surface, volume) effects**
**We have consistently requested a spectrum of species ****(Run-2, 3 Beam Use Proposals)**
**This is now tempered with reality from CAD guidance**
**Makes choice of “A” all the more important, since you get only one per running period**
**Concern is that we will not vary it *****enough:***
**All of the action seems to be at low N****part**

- Log10(Nbinary)

- PHENIX Preliminary

- 29-Sep-03

## Spin Prospects in Run-5

**Run-3 Preliminary result based on **
**<P> = 26%**
**0.35 pb****-1**** recorded **
**For future projections:**
**Run-4 (37 weeks only)**
**<P> = 40%**
**0.5 pb****-1**** recorded**
**Factor 2.8 improvement in statistical error**
**Run-5 (27 weeks scenario)**
**<P> = 50%**
**1.2 pb****-1**** recorded**
**Factor 6.8 improvement in statistical error**

- 29-Sep-03

## Run-6

**27 weeks**
**Au+Au 62.4 GeV**
**5+19 weeks**
***Some***** rare channels**
**ISR comparison**
**37 weeks**
**Au+Au 62.4 GeV**
**5+19 weeks**
***Some***** rare channels**
**ISR comparison**
**p+p 500 GeV**
**5+2 weeks**
**Beam development**
**New A****LL****(********0****)  **

- 29-Sep-03

## Why 62.4 GeV?

**Select an energy to make the suppression go away**

- RAA ~  0.4
- (130 GeV)
-                           RAA~0.2
-                          (200 GeV)

- RAA ~  2.0
- (17 GeV)

- RAA ~1.5
- (31 GeV)

***At a ************s  that still allows “full” coverage in p******T******.***
**Nota Bene: **
**RHIC luminosity scales as *****s***** (i.e., E****2**** )**
**ISR p+p comparison data **

- 29-Sep-03

## Run-7

**27 weeks**
**p+p 200 GeV**
**5+19 weeks**
**Spin***** production *****run**
**“****Ultimate” comparison set**
**37 weeks**
**p+p 62.4 GeV**
**5+5 weeks**
***Some***** rare channels**
**ISR *****extension***
**(No species change)**
**p+p 200 GeV**
**5+22 weeks**
**Spin***** production *****run**
**“****Ultimate” comparison set**

- 29-Sep-03

## Run-8

**27 weeks**
**Au+Au 200 GeV**
**5+19 weeks**
**“****Penultimate” Au+Au run**
**Needed to access Upsilons**
**37 weeks**
**Au+Au 200 GeV**
**5+29 weeks**
**“****Ultimate” Au+Au run**
**Needed to access Upsilons**

- 29-Sep-03

## Run-8+

**Run-8+**

**27 weeks**
**p+p 500 GeV**
**5+19 weeks**
**“****Penultimate” ****spin run**
**37 weeks**
**p+p 500 GeV**
**5+29 weeks**
**“****Ultimate” spin run**
**Approaches original RSC goal of 800 pb****-1**
**(Modulo CAD remarks re optimistic out-year projections in PHENIX ****Beam Use Proposal.. )**

- 29-Sep-03

## Summary

**PHENIX successes in Runs 1-3 have paralleled those of the accelerator **
**Ongoing, productive enterprise engaged in timely publication of an extraordinarily broad spectrum of results (Au+Au, p+p, d+Au)**
**Proposed program will extend **
**Investigation of rare processes to address fundamental questions in heavy ion physics**
**Demonstrated spin physics capabilities to higher p****T**** and to new channels**
**Proposed program depends critically on timely development of luminosity and polarization through extended periods of beam development and steady running**
**Immense benefit from incremental cost of additional weeks of running time**

- 29-Sep-03

## On Energy Scans

**Nearly all phenomena measured thus far exhibit smooth variation with energy:**
**Those that don’t(?)****(e.g., kaon slopes)****already present in pp data (next slide)**
**Absent compelling arguments, and given **
**Natural smearing from Fermi momentum**
**Scarce beam hours**
**Give higher priority to investigating with highest possible sensitivity the signals that are new at RHIC**

-  **K****–****/K****+**

**p/p**

- 29-Sep-03

- 29-Sep-03