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

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

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

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

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: -2.2<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

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

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

MuID HV Status 88000 90000 92000 88000 90000 92000 Select more than 88000 90000 92000 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 88000 90000 92000 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

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

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

Summary PHENIX took polarized proton-proton collision data at √s = 200 GeV with 350 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

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