Measurements of J/ψ with PHENIX Muon Arms in 2003 p+p Collisions

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1 Measurements of J/ψ with PHENIX Muon Arms in 2003 p+p Collisions
東京工業大学　理工学研究科 神原　信幸 　for the PHENIX Collaboration 日本物理学会　2003年　秋季大会 2003年9月11日

2 Content 1. Physics motivation 2. PHENIX Muon Arms
3. Detector Performance 4. J/ψ Mass 5. J/ψ Polarization 6. Summary 2003年9月11日　　日本物理学会秋季大会

3 Physics Motivation Spin Structure of Proton
There is theoretical ambiguity for J/ψ production mechanism Cross section for J/ψ production, J/ψ Polarization 2003年9月11日　　日本物理学会秋季大会

4 J/ψ Polarization J/ψ polarization can distinguish these models
There are three J/ψ production models. Color Singlet Model (CSM) λ> 0 Transverse Color Evaporation Model ( CEM)　λ= 0 Unpolarized Color Octet Model (COM)　 λ < 0 Longitudinal J/ψ θ* is the angle between the μ in the J/ψ rest frame and J/ψmomentum direction. + Momentum direction J/ψ polarization can distinguish these models 2003年9月11日　　日本物理学会秋季大会

5 PHENIX Muon Arms North Muon Arm became operation in 2003 Run μ Beam
Muon Tracker (MuTr) Measurement of momentum Muon Identifier (MuID) Muon identification Trigger Counter μ Beam Geometry Acceptance North : 1.2 <η< 2.4 South: <η<-1.2 Muon range cut off ~ 2GeV/c South Muon Arm 2001~ North Muon Arm: 2002~ Longitudinal Polarization average 27% GeV Proton-Proton Collision 2003年9月11日　　日本物理学会秋季大会

6 Muon Trigger by MuID MuID is divided by 4(“Quadrant”) z direction
Coincidences in z direction at each Quadrant make muon road for trigger signal. z direction Quadrant Look Up Table Horizontal Muon Trigger signal single muon dimuon Quadrant Quadrant Vertical 2003年9月11日　　日本物理学会秋季大会

7 Trigger Circuit Efficiency
0.2 1 0.4 0.8 0.6 Efficiency Run Number 88000 92000 90000 0.95 Hit Information from MuID Trigger electronics Trig Signal Trigger Emulator Trigger Emulation Recorded by DAQ using Minimum Bias events 2003年9月11日　　日本物理学会秋季大会

8 MuID HV Status 88000 90000 92000 88000 90000 92000 Select more than
Run Number 0.6 0.8 1 0.2 0.4 D.F 0.6 0.8 1 0.2 0.4 D.F Run Number South MuID North MuID Select more than 30 minutes Run 2003年9月11日　　日本物理学会秋季大会

9 J/ψ Mass First Detection J/ψ with North Muon Arm Invariant Mass (GeV)
3 1 2 4 5 6 Data Sample: Dimuon Trigger Integrated Luminosity: 143 nb (~50% of run3pp (350 nb ) ) Dimuon sample : 3M J/ψ: ~ 227 J/ψ’s Expected number of J/ψ: 600 (North and South) -1 -1 2003年9月11日　　日本物理学会秋季大会

10 How can we determine J/ψ Polarization?
λ = 1 Transverse λ = 0 Unpolarized λ = -1 Longitudinal Yield (Arbitrary unit) Pt(J/ψ) > 2 GeV/c Using Pt(J/ψ) distribution by Run2 GRV94 1 0.4 0.2 0.6 0.8 J/ψ number for evaluating error: 200 (Pt(J/ψ)>2Gev/c) 2003年9月11日　　日本物理学会秋季大会

11 Summary PHENIX took polarized proton-proton collision data at √s = 200 GeV with integrated luminosity in 2003 Run. North Muon Arm was newly installed in 2003 Run. Muon Trigger at both Arms were working well. J/ψ was measured with both Muon Arms. We confirm J/ψ Polarization is measurable. 2003年9月11日　　日本物理学会秋季大会

12 J/ψ Mass South Arm Invariant Mass (GeV) 3 1 2 4 5 6
3 1 2 4 5 6 Data Sample: Dimuon sample Integrated Luminosity: 143 nb (65% of run3pp) Dimuon sample : 1M J/ψ: ~ 98 J/ψ’s -1 2003年9月11日　　日本物理学会秋季大会