1. STAR W.B. Christie, BNL RHIC Coordination meeting January 17, 2006 Outline Summary of STAR’s request for Run 6 Physics objectives Comments on Sam’s Draft Run Plan

2. STAR STAR Run Plan for 20 week RHIC Run Star RUN request is for polarized pp beams, at √s = 200 GeV, for all Physics running. A “mid-point projection” for integrated luminosity for ~11.5 wks gives ~ 45 pb -1 delivered → gives 15 pb -1 sampled at STAR Note: exact breakdown of time, and order, of transverse (~ 5 pb -1 sampled) and longitudinally (~ 10 pb -1 sampled) polarized beams to be finalized. For now, STAR would like to reserve the possibility to change choice of spin orientation up to 2 times during the √s = 200 GeV running period. STAR also supports a limited period of “500 GeV” Collider commissioning. Limited meaning sufficient to confirm work done since last “500 GeV” commissioning (e.g., ring re-alignment), and make next step forward. Hopefully this means something on the order of 2 to 3 days.

3. STAR Jet (Run5 data) under analysis 2005 Actual statistics Jet yields from run5 data for Jet-patch trigger high tower trigger And actual statistics for A LL ~2.4M events ~0.9M events

4. STAR Inclusive Jet Production – STAR Run 6 Projections Measurement should be sensitive at standard GRSV model prediction level with jet patch trigger!

5. STAR Basic physics Goals Ideas to be tested using FPD++ in Run6 Prototype for FMS (RUN7) Discriminate dynamical origin of the forward A N –Measurement of jetlike events and A N for those Similar to FPD (left, right) but with larger active area Measure shape of forward jet –Measure direct photons cross section, possibly A N --- separation of   and direct gamma Continue the study of   asymmetry in pp other

6. STAR Run-6 FPD++ FPD++ Physics for Run6 Run-5 FPD

7. STAR Run 2 Published Result. Run 3 Preliminary Result. -More Forward angles. -More Forward angles. -FPD Detectors. -FPD Detectors. Run 3 Preliminary Backward Angle Data. Backward Angle Data. -No significant Asymmetry -No significant Asymmetry seen. seen. ( Presented at Spin 2004: hep-ex/0502040) Run 3 + Run 5 Preliminary =3.7,4.0 (Presented SPIN 2005 Dubna Sept 27- Oct 1, Absolute polarization still preliminary) ~ 6  from 0 for x F >0.4

8. STAR D. Boer and W. Vogelsang, Phys.Rev. D 69 (2004) 094025 Back-to-back di-jets: access to gluon Sivers function Measurement should be sensitive at level of model predictions Measurements near mid-rapidity with STAR – search for spin-dependent transverse motion preferences inside proton (related to L orbit ) via predicted spin-dependent deviation from back-to-back alignment > 7 GeV trigger jet > 4 GeV away side jet

9. STAR A qualitative advance in understanding the role of orbital motion in the structure of the proton Statistical error projection for A N for inclusive π 0 production as function of p T at fixed x F during Run 6, together with two theory predictions. These projections assume 10 pb -1 with 50% polarization and the acceptance of the FPD++.

10. STAR Quality Factors for Run VI Longitudinal Studies MeasurementIncrease from FOMIncrease from Detector Improvements Increase from Trigger Improvements Bottom Line A LL of jetsx 5 at high E T compared to Run 5 x 3 at high E T due to completion of the BEMC First measurement to distinguish between favored models of gluon polarization A LL of π 0 in the EEMCx 5 compared to Run 5x 1.3 from shielding in tunnel Significant enrichment at low pT from L2 trigger Meaningful measurements in multiple channels A LL of π 0 in the BEMCx 5 compared to Run 5x 2 from completion of BEMC Significant enrichment at low pT from L2 trigger Meaningful measurements in multiple channels A LL of di-jetsx 5 at high E T compared to Run 5 x 9 at high E T (x 3 at low E T ) due to completion of the BEMC Enrichment at low E T from L2 trigger First measurement that is sensitive to x dependence of ΔG/G A LL of direct photons at mid-rapidity x 5 compared to Run 5x 1.5 from completion of BEMC Increased efficiency near threshold from L2 trigger >100K direct photons for 10 pb -1 Sensitive to the sign of ΔG A LL of direct photons at forward rapidity FPD++ will allow isolation cuts for the first time 100K direct photons for 10 pb -1 Sensitive to gluon polarization at low x γ+jet coincidencesOptimize trigger and analysis algorithms before Run 7

11. STAR MeasurementIncrease from FOMIncrease from Detector Improvements Increase from Trigger Improvements Bottom Line A N of π 0 at forward rapidity x 10 compared to previous measurements FPD++ acceptance ~9 times that of the FPD x 2 by de-coupling FPD++ fast and slow read-out Are we seeing quark orbital motion and/or transversity? A N of direct photons at forward rapidity FPD++ will allow isolation cuts for the first time x 2 by de-coupling FPD++ fast and slow read-out 100K direct photons for 10 pb -1 Direct measure of the quark Sivers function A N for jets at forward rapidity and asymmetry of forward jets about thrust axis FPD++ will encompass the jet cone for the first time x 2 by de-coupling FPD++ fast and slow read-out Direct sensitivities to the Sivers (jet A N at 4~5σ) vs. Collins (jet anisotropy) effects A N for back-to-back di-jet opening angle x 4 when compared to previous sensitivity estimates due to di-jet selection by L2 trigger Measure gluon Sivers function Quality Factors for Run VI Transverse Studies

12. STAR RHIC pp performance: Luminosity Fischer/Roser projections 11 weeks of physics running: l STAR delivered luminosity: 45pb -1 l STAR recorded luminosity: 15pb -1 Allowing for 5pb -1 of transverse and 10pb -1 of longitudinal mode running

13. STAR STAR Run 6 Physics Summary Longitudinal running  Significant result for A LL via inclusive jets  π 0 A LL in B/EEMC  Initial sample of di-jets and direct gamma (for ultimate goal of ΔG(x)) Transverse running  Significant result for forward rapidity Sivers via FPD++  Significant result for Sivers function for mid-rapidity di-jets

14. STAR Comments on Sam’s Draft Run Plan for Run 6 STAR would like to maximize the 200 GeV physics running - If less than 45 pb -1 delivered luminosity, we would likely lose either the transverse of longitudinal physics goals. - Have well planned, necessary 500 GeV Collider commissioning. STAR would like to reserve the possibility to change the polarization direction up to 2 times during the 200 GeV physics running.

15. STAR BACKUP & ALTERNATIVE SLIDES

16. STAR Inclusive Jets (Panic 05): Run4 cross section (Mike Miller) Run 3 and 4 combined A LL (Joanna Kiryluk) *) Predictions: B.Jager et.al, Phys.Rev.D70(2004) 034010

17. STAR New Run 6 STAR Detector Additions  Barrel EM Calorimeter (BEMC)  full east side tower readout and trigger (e.g., full barrel!)  east side SMD readout (and re-worked west)  add east preshower readout (continue w/ full commissioning)  Utilize L2 trigger (in addition to increased L0 selectivity)  di-jet trigger  more efficient π o and γtrigger  Shielding for STAR IR in both east and west tunnels  FPD (forward pion detector) → FPD ++

18. STAR TPC: -1.0 <  < 1.0 FTPC: 2.8 <  < 3.8 BBC : 2.2 <  < 5.0 EEMC:1 <  < 2 BEMC:-1 <  < 1 FPD: |  | ~ 4.0 & ~3.7 Layout

19. STAR A N results J. Adams et al. (STAR), Phys. Rev. Lett. 92 (2004) 171801 A N grows with increasing x F for values larger then 0.35 Results from run2 don’t yet discriminate between different dynamics First result for the A N (p T ) was obtained using combined statistics from run3 and run5. There is evidence that the   analyzing power at x F >0.4 decreases with increasing p T

20. STAR pQCD Physics results Unlike at lower energies, the inclusive differential cross section for pion production at 200 GeV is consistent with NLO pQCD calculations at 3.3<η <4.0 As η increases, systematics regarding the comparison with NLO pQCD calculations begin to emerge. The data at low p T are more consistent with the Kretzer set of fragmentation functions.

21. STAR Jet spin asymmetry Is the single spin asymmetry observed for   also present for the jet the   comes from? Answer discriminates between Sivers and Collins contributions Trigger on energy in small cells, reconstruct   and measure the energy in the entire FPD++ Average over the Collins angle and define a new x F for the event, then see if analyzing power increases with x F Expect that jet-like events are ~15% of   events

22. STAR Sample decays on FPD++ The FPD++ is much closer to FPD then FMS will be. We can mimic the FPD trigger and search for the second   around the first With FPD++ module size and electronic dynamic range, the yellow area marks where we have 95% probability of detecting second photon from   decay

23. STAR To do list Put the north module in place Conect the readout electronics and test all readout Finalize the readout and trigger details Perform measurements with 15/pb delivered integrated luminosity (for 4-5  measurement of A N in jet like events) RUN 6 RUN 7

24. STAR Status report Calorimeter cells for free thanks to FNAL / U.Col. and Protvino Cells were refurbished and tested in physics South enclosure in place on STAR west platform, readout in place cell by cell IN SITU tests and cables connected

25. STAR Inclusive Jet Production – STAR Run 6 Projections

26. STAR RHIC pp performance: Polarization RHIC polarization in Run 5 Assumption for projections: 50%

27. STAR D0 Shielding added in Tunnels at STAR DX East to STAR IR West from STAR IR

28. STAR Where do decay partners go? Gain sensitivity to direct photons by making sure we have high probability to catch decay partners This means we need dynamic range, because photon energies get low (~0.25 GeV), and sufficient area (typical opening angles few degrees at our  ranges). di-photon parameters z  = |E 1 -E 2 |/(E 1 +E 2 )   = opening angle M m = 0.135 GeV/c 2 (   ) M m =0.548 GeV/c 2 (  )

29. STAR Planned FMS Wall FMS …. To be installed for RUN7 Expanding the eta coverage -1<  <4 Measurement of the same side correlations Opposite side correlated pions (dijets) – Sivers effect –d-Au (Gluon saturation in Nuclei) Other future objectives –Forward Lepton pairs –Charm –Drell Yan

30. STAR Reconstruction FPD (Forward Pion Detector) proved we can reconstruct forward   in all (pp, dAu, CuCu) environments

31. STAR Separated x F and p T dependence Similar to ISR analysis J. Singh, et al Nucl. Phys. B140 (1978) 189. Shows the data consistency

32. STAR A N (p T ) in run3+run5 at √s=200 GeV Combined statistics from run3 and run5 allowed to distinguish nonzero effect in A N (p T ) plotCombined statistics from run3 and run5 allowed to distinguish nonzero effect in A N (p T ) plot There is an evidence that analyzing power at x F >0.4 decreases with increasing p TThere is an evidence that analyzing power at x F >0.4 decreases with increasing p T Theoretical prediction’s needed (for constraint on Sivers function).Theoretical prediction’s needed (for constraint on Sivers function). Online calibration of CNI polarimeter

33. STAR How to detect direct photons? We have good sensitivity to both photons in decay of known particles, so that unpaired photons become candidates for being “direct”. π 0  M=0.135 GeV BR=98.8% K 0  π 0 π 0   0.497 31%   0.54739%  π 0    0.782 8.9%  ’   0.958 2.1% Other decay modes yield more photons with less Q Background simulations underway

34. STAR Proposed readout

35. STAR STAR RUN 6 plans Original STAR BUR 6 presented to PAC: 20 weeks physics running –Physics goals: Transverse program (Recorded luminosity 10pb -1 ): Role of transversity and parton orbital motion in forward single-spin asymmetries - Sivers effect in di-jet production Longitudinal program (Recorded luminosity 20pb -1 ): Gluon polarization measurements STAR plans with foreseen 18 cryo week run: 13 weeks physics running –STAR is asking for 200GeV physics running only –Physics goals: Assume 11 weeks of 200GeV physics running Transverse program: :Longitudinal program: Clear progress of above BUR physics goals 1.Commissioning period: Longitudinal mode 2.Collect 5pb -1 of transverse data 3.Return to longitudinal data mode (10 pb -1 )