Post on 04-Jan-2016
description
STAR Status/Plan20080215 RHIC Spin Meeting
L.C. Bland
• Local Polarimetry
• Status
• Plan
Effective Analyzing PowerBBC Polarimeter
• Analysis from available run-6 data more complete analysis still to do
• Event data suggests BBC very similar year to year assume same effective analyzing power for run 8
Run-8 Status• Needed to retime bits to “Crawford” scaler due to hardware upgrade
• Timing completed prior to RHIC store 9850 (20080212)
• Run-8 beam polarization using run-6 effective analyzing power
Fill Tstart Tstop PYellow PBlue
9850 0212-0625 0212-0755 51±4% 56±4%
9859 0213-0420 0213-0508 41±3% 51±3%
9866 0214-0250 0214-0444 35±2% 47±2%
9880 0215-0259 0215-0331 47±2% 55±2%
Measurements continuous between Tstart,Tstop only for 9880
Forward Meson Spectrometer
North FMS half before sealing
STAR Plan for Run-8 p+ p
From Gagliardi presentation to 22 January 2008 weekly planning meeting
Physics goals for the 200 GeV p+p run
• Comparison data for FMS CGC search
• 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
What do these need?
FMS Integrated Luminosity Goal = 30 nb-1
0.00
10.00
20.00
30.00
40.00
50.00
60.00
FMS progress during d+Au
• If things don’t break, we will achieve the reduced goal• If things go well, we might end up at ~40 nb-1
• 40 nb-1 is the same nucleon-nucleon luminosity as 16 pb-1 of pp• RdAu reduces somewhat the pp luminosity needed for equal statistics
Original goal
Reduced goal
Red triangles are with final or near-final PMT gains
25 nb-1 as of midnight last night
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 recorded with 70% polarization
Transverse spin direct Theory expects repulsive color charge interactions to result in an opposite sign to spin-correlated momentum imbalance for +jet. Magnitude of effect requires >105 events to see significant effect.
Comparison of run-6 data to simulation provides indication that prompt can be extracted. The large acceptance and dynamic range of the FMS is needed to veto daughter from ,… decays.
Expect >0.150K events with E>25 GeV into small fiducial volume in 9 pb-1 sampled.
Bacchetta et al., PRL 99, 212002
What might we expect?
• Anticipate 10 to 24 pb-1 delivered for four weeks of physics production
Goals for the 200 GeV pp run
• FMS reference data– Sample at least 9 pb-1 with fast detectors
• FMS transverse spin asymmetry measurements– Sampled figure of merit (P2L) at least 3.8 pb-1 with fast detectors– Equivalent to 9 pb-1 at 65% polarization
• Slow detector measurements for non-photonic electrons– Sample at least 4.5 pb-1
• This requires:– C-AD deliver at least 18 pb-1 (assumes 50% STAR up time)– STAR operate the slow detectors with at least 50% live time– FMS fast detector data recorded when the slow detectors are
both live and dead• Has not been done during this year’s d+Au run
• Was done during Run 6 p+p