# Presentation: 572786

## STAR Run-8 Achievement & Summary 

**Akio Ogawa **
**for the                    Collaboration**
**RHIC-AGS Users Meeting**
**29 May 2008**
**At BNL**

## STAR Run8 Goals

- Main Physics Goals
- Gluon saturation in relativistic heavy nuclei
- Transverse single spin asymmetries of forward 0
- (Transverse single spin asymmetries of gamma-jet)
- (x-dependence of gluon polarization)
- Non-photonic electron, Upsilon and D-mesons
- Low energy AuAu test run
- Detector Upgrades:
- Commissioning of pp2pp
- Commissioning of Forward Meson Spectrometer (FMS)
- Commissioning of DAQ1000
- Commissioning of TOF

## STAR Run8 (Modified) Goals

- Main Physics Goals
- Gluon saturation in relativistic heavy nuclei
- Transverse single spin asymmetries of forward 0
- (Transverse single spin asymmetries of gamma-jet)
- (x-dependence of gluon polarization)
- Non-photonic electron, Upsilon and D-mesons
- Low energy AuAu test run
- Detector Upgrades:
- Commissioning of pp2pp
- Commissioning of Forward Meson Spectrometer (FMS)
- Commissioning of DAQ1000
- Commissioning of TOF

## 1st part

- Main Physics Goals
**Gluon saturation in relativistic heavy nuclei**
**Transverse single spin asymmetries of forward ********0**
- (Transverse single spin asymmetries of gamma-jet)
- (x-dependence of gluon polarization)
- Non-photonic electron, Upsilon and D-mesons
- Low energy AuAu test run
- Detector Upgrades:
- Commissioning of pp2pp
**Commissioning of Forward Meson Spectrometer (FMS)**
- Commissioning of DAQ1000
- Commissioning of TOF

## 2nd part

- Main Physics Goals
- Gluon saturation in relativistic heavy nuclei
- Transverse single spin asymmetries of forward 0
- (Transverse single spin asymmetries of gamma-jet)
- (x-dependence of gluon polarization)
**Non-photonic electron, Upsilon and D-mesons**
**Low energy AuAu test run**
- Detector Upgrades:
**Commissioning of pp2pp**
- Commissioning of Forward Meson Spectrometer (FMS)
**Commissioning of DAQ1000**
**Commissioning of TOF**

## STAR Setup 2008

**STAR Setup 2008**

_**Charged Particle Tracking:**_
**Main TPC**
**  ****1/24 with DAQ1000**
**Forward TPC (FTPC)**

_**Particle ID:**_
**MRPC ToF (parts)**
_**Calorimetry:**_
**Photon Multiplicity Detector (PMD)**
**Barrel EMC**
**Endcap EMC**
**Forward Meson Spectrometer**

_**Event Characterization & Trigger:**_
**Beam-Beam Counter (BBC)**
**Zero Degree Calorimeter (ZDC)**
**Forward Pion Detectors (FPD)**

## Why is forward rapidity interesting? 

- Forward scattering probes asymmetric partonic collisions
- Mostly scattering of
**	****	****high-x valence quarks (with known & large polarization)**
**	****	**0.25 < *x**q* < 0.7** **
**         **      on
- 	         **low-x gluons**
- 		0.001 < *x**g* < 0.1

**N**

**N**

********

******q**

******g**

**P****N**

**x****q****p****N**

**x****g****p****N**

********

********

**P****N**

## p+p and d+Au  0+0+X correlations with forward 0

**Conventional shadowing will ****change yield, but not angular correlation**
**Coherent effects such as CGC evolution will ****change the angular correlation**
**Sensitive to *****x******g***** ~ 10****-3**** in pQCD**** scenario; ****few x 10****-4**** in CGC**** scenario.**

**BRAHMS**

**STAR**

**PRL 97, 152302**

- Back-to-back correlation

## Run8 integrated luminosity at STAR

**Run8 integrated luminosity at STAR**

**Triangles are with final or near-final PMT gains**

**Original goal**

**Reduced goal**

**Diamonds show data taken with a broad range of HV settings**

**Also have ~660M FMS+fast-detector minbias events**

**Final total:  49 nb****-1**

- dAu Slow Luminosity (nb-1)

**dAu**

- 87% of goal

- CGC reference data

- Sampled 7.8 pb-1

- Integrated Luminosity (nb-1)

- Goal 9 pb-1

**pp**

## Forward single-spin asymmetries in STAR

- Large transverse single-spin asymmetries at large xF
- xF dependence matches Sivers effect expectations qualitatively (but not quantitatively)
- pT dependence at fixed xF not consistent with 1/pT expectation of pQCD-based calculations

**arXiv:hep-ex/0801.2990**

## Forward single-spin asymmetries

**Forward single-spin asymmetries**

**Acceptance of FMS and projected RHIC performance will enable...**
** ****Further reach for inclusive ************ and heavy mesons**
** ****Spin-dependent near-side correlations (********************) ******** separation of Sivers and Collins effects**
** ****Spin-dependent away-side correlations (************-jet) ******** isolation of Sivers effect**
** ****Embark on spin-dependent inclusive ******** and ********+jet**

**Projections for 9 pb****-1**** P=70%**

## AN and Sivers and Collins effect

**Sivers mechanism****:** Correlation between nucleon spin and parton kT

**A****N ****and Sivers and Collins effect**

**Phys Rev D41 (1990) 83; 43 (1991) 261**

**Nucl Phys B396 (1993) 161**

**Both effects can contribute to inclusive ****π****0**** A****N**
**Need to go beyond inclusive ****π****0**** detection to separate them **
**jets ****and ****direct photons****, or**** ****π****-****π**** ****correlation in a jet**** **** **

- Asymmetry in hadrons in jets

- Asymmetry in jet/photon production

## Sampled 1.6 pb-1

- Sampled 1.6 pb-1

- Goal 3.8 pb-1

- Integrated FMS FOM P2L (nb-1)

-  Extend xF and pT range for forward single-spin asymmetries
-  Separation of Collins and Sivers
**Significant extension, but well short of what we had intended to achieve**
-  Study direct photon asymmetries in forward direction
**Probably not practical with the current limited data set**

**Transversely Polarized p+p FoM (P****2****L) at STAR**

**Using reported CNI values**

**Only 43% of goal, after calibration from jet**

## FPD to FMS

**Run3-5 FPD **
**Inclusive ********0**** cross sections **
**A****N**** for inclusive  ********0 ****production**

**FPD to FMS**

**RUN3 dAu =only one module (South)**
**At deuteron side (west)**
**Inclusive ********0**** cross sections in dAu and RdA**
**Forward-mid rapidity particle correlations**

## FPD to FMS

**47 x more area**
**> Order of magnitude more luminosity **

**Run8 and beyond:  FMS **
**FMS will provide full azimuthal coverage for range 2.5 ******** ******** ******** 4.0**
**broad acceptance in x****F****-p****T**** plane for inclusive ********,************,********,K********,... production in p+p and d(p)+Au**
**broad acceptance for ************ and   ******************** from forward jet pairs to probe low-*****x***** gluon density in p+p and d(p)+Au collisions**

**d**

**Au**

## Forward Meson Spectrometer (FMS)

**New FMS Calorimeter**
**Lead Glass From FNAL E831**
**804 cells of 5.8cm********5.8cm********60cm**
**Schott F2 lead glass**

**Loaded On a Rental Truck for Trip To BNL**

**Forward Meson Spectrometer (FMS)**

## Forward Meson Spectrometer for Run8

## Run 6 resolution of 

**Run 6 resolution of **
******(M********)/M********~10%**
**should be possible.**

**Need multiple iteration through the data since pion and photon energy get spread over several towers.**

## Calibration is ongoing

**Calorimeter stable at level of ~1%.**

- Minimal run-by-run dependence in mass peak observed

**Entire Run 8 data set should become quickly available with final calibration.**

**Calibration is ongoing**

- LED system : critical calibration tool

- MIT (LED optics)
- UC Berkeley/SSL (flasher boards)
- Texas / Protovino / BNL (assembly)
- SULI program (Stony Brook students) / BNL
-                   (control electronics)

## FMS Summary and Future

** **
** ****Forward Meson Spectrometer (FMS) is constructed & took data in run8!**
**	**
**	****Low-x physics (Can we see Gluon saturation? CGC?)**
**	****Separate Sivers from Collins**
**	****	****“****Jet-like” events, or pi0-pi0 **
**	****	****Near and away side jet-pi0 correlations**
**	****Heavier mesons? **
**	****              ****Eta, Ks, J/psi...****	**

** ****With Future running, Direct Photon + Jet to test “sign change” **
**of Sivers function****	**

## Heavy Flavor Physics in Run8

**Heavy Flavor Physics in Run8**

- High-precision non-photonic electron
- SVT+SSD removed ~ x10 reduction of BG
- Staged L0 Trigger:
- d+Au  : ~90x statistics (run3)
- p+p : ~30x statistics
-  Υ
- d+Au L2 trigger sampled 35 nb-1
- expected yield: ~ 240
- (separation of 3 S states unlikely)
- D0
- d+Au Minimum bias dataset: 46 M events
- >2x statistics from previous d+Au run3

## Largest Background source on inclusive electrons so far: Conversion electrons from SVT+SSD material

SVT/SSD removed (Run8)
     Radiation length reduced ~1/10

Compare the e/h ratio to run3 corresponding results, we find inclusive electrons decrease to ~ 0.10 

Less material decreases relative error by factor ~10

- SVT/SSD removed (Run8)
-      Radiation length reduced ~1/10
- Compare the e/h ratio to run3 corresponding results, we find inclusive electrons decrease to ~ 0.10
- Less material decreases relative error by factor ~10

**NP Electrons in STAR: Inclusive/Background**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Compare the e/h ratio to run ****III**** ****corresponding results, we find inclusive electrons decrease to 0.10.**

**Removal of SVT+SSD : Impact on Heavy Flavor**

**Electron hadron ratio    run8/run3    **

**Charm production via NPE(EMC), D****0****, TOF (e and muon) are all consistent**
**Next crucial check: NPE with reduced material by order of magnitude **

## d+Au & pp integrated luminosity at STAR

- MinBias usable Events

- High Tower Integrated Luminosity

- Goal = 30 Mevts

- Goal = 30 nb-1

- Recorded 46 Mevts

- 153 % of goal

- Sampled 36 pb-1

- 120 % of goal

**92% have Vz ******** 50 cm**

**MinBias Vertex (Z) Distribution**

**d+Au & pp integrated luminosity at STAR**

**dAu**

**dAu**

- pp “slow” Luminosity (nb-1)

- Goal 4.5 pb-1

- Sampled 3.1 pb-1

- 69% of goal

**pp**

## Low Energy (9 GeV) Test Run

** ****Find Collisions ******
** ****Gain understanding of triggering issues ******
** ****Determine Luminosity ******

**Luminosities**
**  ****~ 1 to 3 x 10****23**** cm****-2**** s****-1**
**Collisions rates**
**         ****= ******** x L**
**         ****= (6 b)(1.5 x 10****23**** )**
**         ****= ~ .9 Hz**
**Our present understanding of our trigger efficiency, and Angelika’s luminosity, agree very well (~ 20%)!**

## Au+Au @ √sNN=9 GeV: Preliminary Analysis

**Uncorrected p****⊥ ****spectra**

**Raw multiplicity**

**PID (dE/dx only)**

**Note: Plots should be taken ****only**** as ****illustrative**** of data quality and analysis capability**

**George Stephans’s Talk on Friday**

## DAQ1000 commissioning

**Laser event (plus pileup)**

**DAQ1000 commissioning**

** ****One sector of the TPC (1/24) instrumented with DAQ1000 electronics**
** ****Commissioned/integrated and took part of physics data taking by early run8**
** ****Routine operation at 250 Hz with TOF triggered events**
** ****Speed test:  operated at 1 kHz with only 5-7% dead time (<<100 us/event)**
** ****On schedule to full implementation for run9**

- Replace full TPC readout chain to record full delivered luminosity
- Dead-time ~ 0
- Data taking speed ~x10

## Multi-gap Resistive Plate Chamber Time-of-Flight

- Joint project between USA & China
- In detector research

- 1 tray   in some of runs 2-7
- 5 trays  in run 8 behind DAQ1000
- ~75% in run 9
- 100% in run 10 (Q2,FY09)
**-0.9<********<0.9, 0<********<2******
**23,000 ch (120 trays)**

**  ****Total TOF triggered events 76M for physics and calibration in p+p**
**  ****Provide crucial information for pileup rejection**
**  ****Preliminary calibration :  81ps (goal <100ps) **

**TOF+TPX from run8: **
** ****Non-photonic electron at low p****T ****with low material **
** ****25x statistics for PID spectra in p+p**
** ****>10x S/B ratio of Resonances (********) in p+p **** **

**Posters by Zebo Tang and Jin Fu**

## Roman pots installed east and west downstream of STAR (thanks, C-AD!)
pp2pp data acquisition integrated into STAR trigger and DAQ systems
Inserted Roman pots into the beam pipe during last 2 hours of p+p run
Observed pp2pp detector rates as expected
No impact on background levels in STAR mid-rapidity detectors
Physics in Run 9

- pp2pp data acquisition integrated into STAR trigger and DAQ systems
- Inserted Roman pots into the beam pipe during last 2 hours of p+p run
- Observed pp2pp detector rates as expected
- No impact on background levels in STAR mid-rapidity detectors
**Physics in Run 9**

**For the future:  pp2pp @ STAR**

## STAR Run8 Goals & Luminosity

| System | Trigger | Goal | Acquired |
| --- | --- | --- | --- |
| d+Au | FMS | 60/nb (reduced 30/nb) | 49/pb |
| d+Au | BEMC HT | 30/nb | 36/pb |
| d+Au
 | MinBias | 30M events | 46M events |
| p+p | FMS | 9/pb | 7.8/pb |
| p+p | FMS | P2L = 3.8/pb | P2L = 1.6/pb
 |
| p+p | BEMC HT | 4.5/pb | 3.1/pb |
| p+p | MinBias | Few k events | Few k events
(76M Events with TOF+TPX) |

**STAR Run8 Goals & Luminosity**

## STAR Run8 Summary

- Main Physics Goals
- Gluon saturation in relativistic heavy nuclei
- Transverse single spin asymmetries of forward 0
- (Transverse single spin asymmetries of gamma-jet)
- (x-dependence of gluon polarization)
- Non-photonic electron, Upsilon and D-mesons
- Low energy AuAu test run
- Detector Upgrades:
- Commissioning of pp2pp
- Commissioning of FMS
- Commissioning of DAQ1000        All 3 used for Physics
- Commissioning of TOF

**Short run didn’t allow us**
**to complete some of **
**original goals**

**“****Short” run8 was successful**
**Exciting physics will be coming out**