99/11/12 PHENIX November Co re 1 ΔG ΔG Measurement with Measurement with the Heavy Quark the Heavy Quark Production Production • ΔG Status and probes for it • Prediction of A LL in the PHENIX • A LL uncertainties and ΔG sensitivity – J/– epair – single electron • Reduction of electron background • Summary Hiroki Sato Kyoto Univ./RIKEN PHENIX November Core
ΔG Measurement with the Heavy Quark Production. Hiroki Sato Kyoto Univ./RIKEN PHENIX November Core. ΔG Status and probes for it Prediction of A LL in the PHENIX A LL uncertainties and ΔG sensitivity J/ e pair single electron Reduction of electron background Summary. - PowerPoint PPT Presentation
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99/11/12 PHENIX November Core 1
ΔGΔG Measurement with the Measurement with the Heavy Quark ProductionHeavy Quark Production
• ΔG Status and probes for it
• Prediction of ALL in the PHENIX
• ALL uncertainties and ΔG sensitivity– J/– e pair
– single electron
• Reduction of electron background
• Summary
Hiroki Sato Kyoto Univ./RIKENPHENIX November Core
99/11/12 PHENIX November Core 2
Status of Status of ΔGΔG MeasurementMeasurement
1/2 = (1/2)+G+L+LG
~ 0.3
ΔG
Polarized Deep Inelastic Scattering
Direct measurement with polarized p-p collisions( RHIC)
-1
0
1
2
3
4
Large uncertainty for indirect measurement
quark spin gluon spin
orbital angular moment
proton spin
Altarelli. et.al (1997)Q2=
E155(1999)Q2=5GeV2
SMC(1997)Q2=10GeV2
99/11/12 PHENIX November Core 3
Probes for Probes for ΔG ΔG MeasurementMeasurement
Gluon Compton
Charmonium Production
Open Heavy QuarkProduction
High-pT prompt
e+e-, +-
e+e-, +- ,ehigh-pT single e,eD, D
G(x)ALL
simulation
?Experiment
99/11/12 PHENIX November Core 4
SimulationsSimulations
• Purposes
– ALL expectation with PHENIX using some models of G(GS-A,B,and C)
– Yield and background study → estimation of statistical and systematic errors.
• PYTHIA 5.7 with GRV94-LO and JETSET 7.3 for event generation.
s=200GeV
• Simple acceptance cut (||<0.35 for Central Arms and 1.1<||<2.3 for Muon Arms)
• normalization to 32 or 320pb-1
99/11/12 PHENIX November Core 5
AALLLL Prediction at PHENIX Prediction at PHENIX
1.12
ˆ
M
s
1.5
2
5
a
AQQgg
LL
XQQpp
LL
xG
xG
xG
xG
xx
)(
)(
)(
)(
),(
2
2
1
1
21
cos*
ΔG
(x
)
M.Karliner and R.W.Robinett(1993)T.Gehmann and W.J.Stirling(1995)
aLL
x
Me(GeV)
1.711.631.02
AL
L
ALLpp→bb X
μeGS-A
GS-B
GS-C
GRV-94 LOfor unpol.PDF
99/11/12 PHENIX November Core 6
AALLLL Experimental Errors Experimental Errors
PB1,2 Beam Polarization ~ 0.7(RHIC) N++( N+ -) Number of events
L++( L+ -) Luminosity
• Statistical Error
• Systematic Errors PB 1 ,2 → ALL/ALL ~20%
(L+ - /L++) → ALL~10 ー 4
– Nbg/Nsig ,ALLbg
LNLN
LNLN
PPA
BBLL
21
1exp
)(1
.)(21
NNNNPP
statA tot
totBB
LL
) (if sigbgbg
LLsig
bgLL NNA
N
NA
+‐: Beam Helicity
99/11/12 PHENIX November Core 7
DimuonsDimuons
M (GeV/c2)NJ/(pT>2GeV)~120k events
→ALLJ/ (stat.)~ 0.006
N/K /NJ/~ 0.15
ALL/K ~0.007
→ ALL J/ (syst.)~0.001
ALLJ/
G
production mechanism of the charmonium
Yie
ld p
er B
in(0
.2G
eV/c
2 )
pT()>2GeV/c
bottom
J/ ( color singlet model )
/K
320pb-1 s=200GeV
99/11/12 PHENIX November Core 8
ee pairs pairs
• background of electrons (0Dalitz decay and conversion) can be reduced
• b/c separation is under studying → important because ALL is different