1. Status DG Section of Whitepaper J. Sowinski, A. Deshpande, Y. Goto, M. Stratmann,B. Surrow, W. Vogelsang

2. 4/21/2008RSC Meeting BNL J. Sowinski 2 Our charge from Steve “…should probably include brief updates on present projections of Delta G and transverse spin sensitivities to be attained in the remaining 200 GeV running” “Will there be sufficient integrated luminosity to attain the desired Delta G sensitivities in photon and photon-jet production? If not, are there alternatives?” For you in this talk: What is missing? What is too much? Refine the message(s)?

3. 4/21/2008RSC Meeting BNL J. Sowinski 3 Only room for the most prominent results STAR incl. jets PHENIX incl. p 0 s

4. 4/21/2008RSC Meeting BNL J. Sowinski 4 These results from RHIC have had a strong impact on our knowledge of DG Global fit D. de Florian, R. Sassot, M. Stratmann and W. Vogelsang

5. 4/21/2008RSC Meeting BNL J. Sowinski 5 Future: Increased statistics for inclusives still have important contributions to make PHENIX 25 pb -1 P=60% DG=0.15 DG=0 Add run 9 to G.A. (Run6)/4

6. 4/21/2008RSC Meeting BNL J. Sowinski 6 Semi-inclusive channels to map Dg(x) STAR di-jets 50 pb -1 P=60% X min = 0.08 X max =0.20 X min = 0.08 X max =0.20 X min = 0.13 X max =0.15 X min = 0.08 X max =0.32 X min = 0.04 X max =0.37 X min = 0.03 X max =0.46 Typical partonic x p T =10 GeV (LO)

7. 4/21/2008RSC Meeting BNL J. Sowinski 7 g-jets limited in statistics at 50 pb -1 but still could have impact x gluon resolution in PHENIX greatly improved with vertex tracker 100% eff. - Perfect BG rejection in STAR for g- jets. Di-jets hard to beat but strong cross check could be possible. 50 pb -1 P=60% GSRV DSSV

8. 4/21/2008RSC Meeting BNL J. Sowinski 8 Placeholder for feasibility of g-jet statistical precision STAR MC simulations – hope to still have something by PAC SMD shower shape bg rejection vs. g efficiency

9. 4/21/2008RSC Meeting BNL J. Sowinski 9 What about lower x gluon ? Dg(x=0.02)/g(x=0.02)~0.05 Central detectors p T =10GeV FMS g - central jet p T =2GeV Q 2 = 10GeV 2 FMS g-jet f correlation for p T =2GeV and estimate significant number of events in 50 pb-1 wrt Dg(x)/g(x)=0.05 What is Dg(x)/g(x) allowed to do for x<0.02? 500 GeV one option. Phenix similar possibility with MPC – Central Cal.

10. 4/21/2008RSC Meeting BNL J. Sowinski 10 W physics means lots of beam time at 500 GeV. What can we do there for DG? Lower x…. The end of this talk but not the work.