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

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. + θ* is the angle between the μ in the J/ψ rest frame and J/ψmomentum direction. J/ψ J/ψ Polarization 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 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. GeV PHENIX Muon Arms North Muon Arm became operation in 2003 Run 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% Proton-Proton Collision 2003年9月11日　　日本物理学会秋季大会

6. Look Up Table Muon Trigger by MuID MuID is divided by 4(“Quadrant”) Coincidences in z direction at each Quadrant make muon road for trigger signal. z direction Quadrant 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. 1 Efficiency 0.95 0.8 0.6 0.4 0.2 0 88000 90000 92000 Run Number Trigger Circuit Efficiency 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. 1 1 D.F D.F 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0 88000 90000 92000 88000 90000 92000 Run Number Run Number MuID HV Status 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. 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) 0 1 2 3 4 5 6 Invariant Mass (GeV) J/ψMass First Detection J/ψ with North Muon Arm -1 -1 2003年9月11日　　日本物理学会秋季大会

10. 1 0 0.2 0.4 0.6 0.8 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 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 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

12. 0 1 2 3 4 5 6 Invariant Mass (GeV) J/ψMass South Arm 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