d Au Progress

1
dAu Progress

• Forward physics (FMS) reduced goal 30 nb-1,
  achieved 3 nb-1
• As of Jan. 7, retuned program to maximize FMS
  sampled luminosity (and increase MinBias
  recording rate)
• On track to completion end of January
• Estimate 1.6 nb-1/day, needs 20 days

2
Luminosity in pp 2008Whats possible with only
6 weeks?

• Expectation 12-24 pb-1 delivered at 200 GeV
• 6-12 pb-1 sampled by FMS
• 3-6 pb-1 sampled by slow detectors

3
Physics from pp 200 GeV

• Comparison data for FMS CGC search
• Binary scaling 30 nb-1 dAu 12 pb-1 pp
• Situation somewhat better, since RdAu lt 1
• 6-12 pb-1 in pp will give reference statistics
  equivalent to dAu for FMS
• Extend xF and pT range for forward single-spin
  asymmetries
• Study direct photon asymmetries in forward
  direction
• Electrons from Charm and Bottom, with low
  material, to resolve STAR/PHENIX discrepancy

4
Forward single-spin asymmetries

• Acceptance of FMS and projected RHIC performance
  will enable
• Further reach for inclusive p0 and heavy mesons
• Spin-dependent near-side correlations (p0-p0) ?
  separation of Sivers and Collins effects
• Spin-dependent away-side correlations (p0-jet) ?
  isolation of Sivers effect
• Embark on spin-dependent inclusive g and gjet

Projections for 9 pb-1 recorded
5
Transverse spin direct g
Theory expects repulsive color charge
interactions to result in an opposite sign to
spin-correlated momentum imbalance for gjet.
Magnitude of effect requires gt105 events to see
significant effect.
Bacchetta et al., PRL 99, 212002
Comparison of run-6 data to simulation provides
indication that prompt g can be extracted. The
large acceptance and dynamic range of the FMS is
needed to veto daughter g from p0,h,
decays. Expect gt150K g events with E?gt25 GeV into
small fiducial volume in 9 pb-1 sampled.
6
Low-energy AuAu run

• Issues with results from 2007 9 GeV AuAu run
• Large backgrounds identified in trigger
• Entire event rate may be from background
• Luminosity may scale below ?2
• Time for viable physics run may be underestimated
  
• Another test run is needed
• Few days at 9 GeV, recording with new trigger,
  sufficient for these tests
• Needs to be scheduled to avoid Quark Matter

7
Looking ahead to Run 9

• This unfortunate situation means we will not make
  progress on our longitudinal spin goals for the
  second year in a row
• STAR will probably request a long longitudinal pp
  run at 200 GeV (with DAQ1000!), and some 500 GeV
  tests following, to start Run 9