Polarization Measurements of RHIC-pp RUN05 Using CNI pC-Polarimeter Itaru Nakagawa (RIKEN/RBRC) On behalf of CNI Polarimeter Group I.G.Alekseev A A.Bravar B G.Bunce B S.Dhawan D R.Gill B H.Huang B W.Haeberli E G.Igo F O.Jinnouchi V.P.Kanavets A K.Kurita H A.Khodinov J Z.Li B Y.Makdisi B A.Nass B W.Lozowski I W.W.MacKay B H.Okada G S.Rescia B T.Roser B N. Saito G H.Spinka L D.N.Svirida A D.Underwood L C.Witten F T.Wise I J.Wood F A.Zelenski B RBRC ITEP A BNL B ANL C Yale U D Wisconsin U E UCLA F Kyoto U G Rikkyo U H Indiana U I StonyBrook U J IUCF K Argonne U L Itaru Nakagawa (RIKEN/RBRC) On behalf of CNI Polarimeter Group I.G.Alekseev A A.Bravar B G.Bunce B S.Dhawan D R.Gill B H.Huang B W.Haeberli E G.Igo F O.Jinnouchi V.P.Kanavets A K.Kurita H A.Khodinov J Z.Li B Y.Makdisi B A.Nass B W.Lozowski I W.W.MacKay B H.Okada G S.Rescia B T.Roser B N. Saito G H.Spinka L D.N.Svirida A D.Underwood L C.Witten F T.Wise I J.Wood F A.Zelenski B RBRC ITEP A BNL B ANL C Yale U D Wisconsin U E UCLA F Kyoto U G Rikkyo U H Indiana U I StonyBrook U J IUCF K Argonne U L
Polarimetry: Impact on RHIC-SPIN Physics Asymmetries Single Spin Asymmetries Double Spin Asymmetries Polarization measurement by Elastic pp/pC Polarized proton Recoil carbon 90º in Lab frame Carbon target P beam Required Accuracy ~5%
pC Analyzing Power A N (100GeV) L. Trueman hep-ph/ Recoil Carbon Need to Measure Recoil Energy t-dependence
RHIC Polarimetry
Characteristics of pC polarimeter Large Cross Section Solid target 20 sec./measurement for ~ 2% statistics. Immediate feedback to accelerator operation “Bunch by Bunch” beam polarization structure Polarization profile measurement High Event Rate
pC Polarimeter Setup Ultra thin Carbon ribbon Target (3.5 g/cm 2 ) Si strip detectors (TOF, E C ) 18cm 10mm 2mm pitch 12 strips 72 strips in total deg Physics deg Physics Physics asymmetry Up-Down (Radial) Cross (Forbidden) False asymmetry Redundancy Systematic/Consistency Check Redundancy Systematic/Consistency Check
Strip by Strip Consistency 2 Distribution of sin( ) fit –Well Distributed around 1 –Evidence of Consistent Polarization Measurements by individual strips
Carbon Target L Energy Correction T deposit (keV ） ) Time of Flight t meas [ns] (adc)(DeadLayer) (t 0, x ) Kinematic Fit
Energy Correction (Stability) Stability Error 9 ~ 11 g/cm 2 Stability Error 9 ~ 11 g/cm 2
Online/Offline Polarization
Run5 Polarization Profile 2mm Polarization Count Rate[Hz] Polarization
Uncertainties & Summary Energy Scale3~4 % Event Selection1% Polarization Profile Normalization from Run48.5% Total (Absolute)~ 9% Relative Run5Smaller
Backup Slides
Azimuthal Angle Distribution Fill Number angle [deg.] Fill Number angle [deg.] = 0 deg.
Energy Correction Typical Thickness 〜 50 g/cm 2 Kinetic Energy = ４００ keV Correction Observation Energy Loss [keV]
Event Selection Dependence 2 vs 3 Cut Consistency Systematic Error 22 33
Event Selection Error Event Selection Error ~ 1% ( was 3% in Run3,4) Event Selection Error ~ 1% ( was 3% in Run3,4)
Strip by Strip Consistency ~ sin( ) fit ~ mm pitch 12 strips
Road Map to Finalize the Analysis Remaining Major Items –Continue QA (3 weeks) Suspicious bunch, strips –Study Off-Centered Target Measurements(2 ~ 4weeks) Fill by Fill Analysis Polarization Profile –Normalization with Jet (4 weeks)
Energy Correction (Strip by Strip Consistency) Strip Number （７２ Total ） Energy Correction( g/cm 2 ) All Detectors are made from same wafers Any inconsistency should be accounted as sys
Energy Correction (Strip by Strip Consistency)
Systematic Error Summary(1) BlueYellow Energy Calibration--- strip-by-strip consistency 3.5 (1)4.5 (2) Event Selection33 Stability Total10.1 (9.1)12.3 (11.3) Energy Correction [ug/cm 2 ] ( ):Relative Error
Contents Kinematics Reconstruction – source energy calibration –Deadlayer energy correction –Systematic error estimation(1) Polarization (1st Path Analysis Results) –Online/Offline –Event selection 2 /3 –Strip by strip consistency sin( ) fit –Systematic error estimation (2)