CNI polarizations in Run09: Summary A.Bazilevsky For the RHIC CNI Group March 26, 2010 RSC meeting

Run9 results Released on Feb 4, 2010: Gives: Fill#, Polarization, Stat. error, Syst. Error Global syst. errors (to all fills) Short analysis description: NOTE_2009_Polarizations_RHIC.txt Detailed analysis description: pC_2009.pdf

Briefly Hjet: Absolute beam polarization Continuously running in a fill Absolute stat. uncertainty in a fill: ~50% fills at  s=500 GeV and ~80% fills at  s=200 GeV Statistics accumulated in many fills used to normalize pC pC (two polarimeters in a ring): 3-4 measurements in a fill (every 2-3 hours) in target scan mode Pol. profile Many more parameters: pol. decay in a fill, pol. vector in trans. plane, beam emittance etc. Polarization for experiments (in collisions), after normalization to Hjet and correction for pol. profile

Run9 results

Systematic Errors

Syst. Errors: HJet Jet normalization, stat: 2.5% for 250 GeV and 1.0% for 100 GeV That’s what existing data gave us Jet normalization, syst (dilution): 2% That’s what we’ve been using since Run4 (molecular contribution) Jet normalization, syst (backgr): 2-3% From the measurements of backgr. asymmetries Run8: %; Run6: %

pC: Time dependence in a fill Time, hr Pol. decay!

pC: average over a fill T p decay – from pC T L decay = 5 hr   Comparison of with T L decay = 5 hr and  (T L decay =  is equivalent to a weighted average) Only few fills showed syst. problems  assign additional syst. error for these fills

pC in 2009: issues and strategy Rate related systematics Particularly at  s=500 GeV Failed to find a way to correct it (rate is defined by prompts which are already cut off by DAQ) Strategy: Two polarimeters in a ring are averaged Fill-by-fill systematic uncertainties evaluated from the comparison between two polarimeters and between pC and HJet

Fill dependence (pC vs HJet) No systematic effect seen on the HJet stat. error level 250 GeV

Fill dependence (pC vs HJet) No systematic effect seen on the HJet stat. error level 100 GeV

Fill dependence (Pol1 vs Pol2) 250 GeV RMS of the variation  12% fill-by-fill syst. uncertainty Not yet normalized to HJet

Fill dependence (Pol1 vs Pol2) 100 GeV RMS of the variation  6% fill-by-fill syst. uncertainty Not yet normalized to HJet

Pol. Profile (all) 100 GeV250 GeV ~0.08~0.40

Pol. Profile (good) 100 GeV250 GeV ~0.08~0.40

Pol. Profile: summary 250GeV: =0.36  0.14; with fill-by-fill variation  GeV: =0.08  0.04; with fill-by-fill variation  0.08 =0.36  0.14  (15  5)% correction from Hjet to experiments =0.08  0.04  (4  2)% correction from Hjet to experiments

Summary Global systematic uncertainties: Blue,  s=500 GeV: 8.3% Yell,  s=500 GeV: 12.1% Blue,  s=200 GeV: 4.7% Yell,  s=200 GeV: 4.7% Run5: 5.9% and 6.2% Run6: 4.7% and 4.8% Run8: 4.2% and 7.2%

Path Forward

Backup

Sookhyun: Background raw asymmetries Target Asymmetry (raw) Beam Asymmetry (raw) Possible Effect on Polarization Blue single 250GeV <2.1% Blue double 250GeV <2.2% Blue 100GeV <1.1% Yellow 250GeV <4.0% Yellow 100GeV <0.9% From Mean  Sigma

pC: pol. Decay in a fill  s=500 GeV 1/T decay Affected by rates! = hours ( =100 hr  1%/hr) Run6: ~150 hours Run8: ~400 hours ~100 hours In a fill: fit to exp(-t/T decay )

pC: pol. Decay in a fill  s=200 GeV 1/T decay = hours ( =100 hr  1%/hr) Run6: ~150 hours Run8: ~400 hours ~100 hours Affected by rates! In a fill: fit to exp(-t/T decay )

pC: Time dependence in a fill  s=500 GeV

Time dependence (pC vs HJet), vs period  s=500 GeV

Time dependence (pC vs HJet), vs period  s=200 GeV

Pol1 vs Pol2  s=200 GeV Yell Blue  s=500 GeV

Pol. Profile: rate dependence  s=200 GeV  s=500 GeV

Horizontal component  ~ |  |<5 0  s=200 GeV  s=500 GeV  ~5 0 |  |<5 0

pC: Intensity Profile Bad profile: Non-gaussian High rate Rate problem? Good profile: Perfect gaussian Low rate Bad profile: Non-gaussian Low rate Target positionig problem?

pC: Polarization Profile pC Scan C target over the beam cross: Target Position Intensity Polarization II PP 2. Obtain R directly from the P(I) fit:   P I Precise target positioning is NOT necessary 1. Directly measure  I and  P : R=0.29  0.07

Normalization for pC (Hjet/pC) Initial normalization from Run4 (  s=200 GeV)

ANAN pC pp