# Presentation: 940043

**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/rbupaug02/PACAug02.htm](http://www.phenix.bnl.gov/phenix/WWW/publish/zajc/sp/presentations/rbupaug02/PACAug02.htm)**_** )**

- 26-Aug-02

## 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**

- 26-Aug-02

## 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/******** measurement)**
**p↑-p↑  : 26-N weeks  ( ********G measurement)**
**Run-5**
** ****Si-Si: (Light ions with sufficient  ∫*****L***** dt  ****             to measure J/********)**
**p↑-p↑: (Towards 320 pb****-1**** at 200 GeV)**
**Notes: **
**Predicated on “Roser model” ******** 3 modes deprecated**
**All running is assumed at √s****NN**** = 200 GeV, with possible exception of development work towards 500 GeV for polarization**

- 26-Aug-02

## The  Collaboration

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

- 26-Aug-02

## 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)**

- 26-Aug-02

## 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)**

- 26-Aug-02

## Run-1 Publications (1)

**“****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)**_

- 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

- 26-Aug-02

## From Run-1 to Run-2

**For 2001 Run:**

- Run-1 (2000)

- 26-Aug-02

## 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**

- 26-Aug-02

## 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 |

- 26-Aug-02

## Run-3 and Beyond

- 26-Aug-02

## 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**

- 26-Aug-02

## MUON IDENTIFIER LEVEL-1 TRIGGER

**MUON IDENTIFIER LEVEL-1 TRIGGER**

**NIM Logic LVL-1 Trigger used during Run-2**
**LVL-1 rejection is not ****required for Au+Au ****until RHIC significantly ****exceeds design luminosity.   **
**LVL-1 rejection is required for lighter species, ****notably p+p and d+Au**
**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)**

- 26-Aug-02

## 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

- 26-Aug-02

## EmCal based PID

**EmCal based PID**

**Now “routinely” using****TOF from EmCal****to extend aperture****for our identified ****hadron analyses**
**Already in use for****HBT**
**Will apply ****to ******** ******** K+K-**

- 26-Aug-02

## TEC  TRD upgrade

**Time Expansion Chamber ******** Transition Radiation Detector**
**TRD upgrades:**
**Install radiators**
**Gas system**
**Previous: P-10**
**TRD: **
**50% Xe, ****10-20% Methane****40-30% He**
**Recirculation**
**General:**
**Previously: 4 planes**
**Now           : 6 planes**
**End result: **
**Increased momentum resolution at high p****T**
**Increased electron ID capability at high p****T**

- TRD
- Radiator

**TR Photon**

- Electron
- Clusters

**Drift Window**

**PUSH******

- 26-Aug-02

## South Muon Arm Improvementsand 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**

- 26-Aug-02

## 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**
**d’s in blue ring**
**Physics questions addressed**
**Parton energy loss in ‘cold nuclear matter’**
**J/******** 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)**

- 26-Aug-02

## TRIGGER RATE (Hz)

*TRIGGER RATE (Hz)*

- collimate beam

- mis-steer

- collimator out

- TIME

- dump yellow

- blue target in

- yellow target in

- collimate blue

**After ********* = 1 m achieved, significant non-collision background observed.  Studied problem with help from RHIC during p+p 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. **

**Background Studies**

**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**

- 26-Aug-02

## 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.**

- 26-Aug-02

## 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**
**N****coll   ****( 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...)**

- }

- 26-Aug-02

## 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 N****coll**** from 71 to 975)**

- PHENIX Run-2 Preliminary Data presented at Quark Matter 2002

- 26-Aug-02

## Run-2 High pT Results (Peripheral)

**PHENIX Preliminary**

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

- 26-Aug-02

## Run-2 High pT Results (Central)

**Q: Do all processes that *****should *****scale with N****coll**** do just that?**
**A: No! **
******Central collisions ****are *****different *****.**
**This is a *****clear***** discovery****of *****new***** behavior at RHIC**
**It is presumably a result****due to formation of ****unusually dense****and opaque matter early****in the collision**
**Intense theoretical ****activity to understand ****dependence on **
**Medium properties(?)**
**Deconfinement(??)**

**PHENIX Preliminary**

- 26-Aug-02

## More (new) Run-2 results

**Observation of jet cones ****(near and away)**
***Trigger***** on high p****T**** ********0**
***Examine***** angular ****distribution wrt trigger**
***Calibrate***** in p-p by ****comparison to ****PYTHIA predictions**
***Apply***** to Au-Au**
***Account***** for complications****due to flow in Au-Au**
**(In progress) **
***Systematize***** yields and ****shapes as a function of centrality**
***Relate***** to suppression **

- 26-Aug-02

## 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**

- 26-Aug-02

## Understanding the Suppression

**Q. Isn’t the suppression just a measure of the (integrated) density?**
**A. Perhaps, but**
**That’s what we’d 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**

- 26-Aug-02

## Expected pT Range in d-Au

**Expected p****T**** 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**
**p****T**** range ‘in excess of’ ****15 GeV/c**

- 26-Aug-02

## 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**

- 26-Aug-02

## 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**
******+********- data****still to come**
**Clearly****statistics****limited****( 24 ********b****-1****    versus****hoped-for****300  ********b****-1****)**

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

- 26-Aug-02

## Charmonium Yields in d-Au

**Use measured ‘PHENIX Preliminary’ p-p data as input to color evaporation model:**
**Reproduces**
**x****F**** dependence**
**p****T**** dependence**
**Total cross section ****( 4.0  ********b versus quoted****   3.8 ± 0.6  ± 1.3 ********b )**
**Use this parameterization to compute expected yields in for 10 week d-Au run**
**Results (next slides)**

**PHENIX****Preliminary**

**PHENIX****Preliminary**

- 26-Aug-02

## J/ ‘Results’ in d-Au (I)

**Broad coverage in **
**x****F****, p****T**** and x****2**
**by combining **
**North Arm**
**Central Arm**
**South Arm**** **

- 26-Aug-02

## J/ ‘Results’ in d-Au (II)

**Excellent ability to measure A******** dependence versus various kinematic variables **
**Again, broad coverage in **
**x****F****, p****T**** and x****2**
**by combining **
**North Arm**
**Central Arm**
**South Arm**** **

- 26-Aug-02

## 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**

- 26-Aug-02

## 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 > 40%**
**Longitudinal polarization at PHENIX IP **
**Physics questions addressed**
**Measurement of A****LL**** via pion production**
**Inclusive (comparison) measurements:**
**J/******** production**
**Open charm production**
**High p****T**** hadron and photon production**

- 26-Aug-02

## 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**

- 26-Aug-02

## 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 p****T**** at x=0 permits ****pQCD treatment**
**Should lead to bounds ****on the product **
**(transversity quark distributions) **
**x **
**(Collins-Heppelman **
** ****fragmentation function)**

- 26-Aug-02

## Assumed Spin Developments

**Spin run is predicated on polarization ****in AGS ≥ 40% **
**To be demonstrated during d-Au run**
**(Soft limit)**
**RHIC**
**Achieve <****L****> ~ 10****31**** 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**

- 26-Aug-02

## Projected Run-3 ALL Measurement

**Projected Run-3 A****LL**** Measurement**

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

- W. Vogelsang

**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 π****0****   cross section and ****NLO pQCD. (next slide)**
**Competes with ongoing efforts at CERN**** ****(next slide).**

- 26-Aug-02

## 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

- 26-Aug-02

## 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 ~10****3 ****(~10****4****) improvement in P****2****L  (P****4****L)**

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

- 26-Aug-02

## 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

- 26-Aug-02

## Run-4: 
We must measure J/ in Au-Au !
(Run-3 d-Au request predicatedon commitment to such a runin Run-4)
Run-5:
Fully operational muon arm+ new triggers
Full exploration of J/ productionversus “Nbinary” ~ A(b)*A(b) via
Run-4 long run with Au-Au
Run-5 light ion runs
Spin
    Continued running to accumulate320 pb-1 at 200 GeV

**We *****must***** measure J/******** in Au-Au !**
**(Run-3 d-Au request predicated****on commitment to such a run****in Run-4)**
**Run-5:**
**Fully operational muon arm****+ new triggers**
**Full exploration of J/******** production****versus “N****binary****” ~ A(b)*A(b) via**
**Run-4 long run with Au-Au**
**Run-5 light ion runs**
**Spin**
**    ****Continued running to accumulate****320 pb****-1**** at 200 GeV**

- Log10(Nbinary)

**Looking Ahead**

- 26-Aug-02

## 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” p****T**** scales (as permitted by luminosity)**
**Begin program of J/******** measurements    **
**(TBD) Obtain comparison data for same in p-p collisions**
**(TBD) Begin spin program.**** **
**Every expectation of a repeat performance for Run-3**

- 26-Aug-02

## Re Npart scaling

**PHENIX has carefully studied both N****coll**** and N****part**** scaling as a function of p****T**
**Clearly N****part**** is *****not***** the relevant scaling variable**
**Reference:**** nucl-ex/0207009**

- 26-Aug-02