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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 1 Measurement of the leptonic and hadronic decays of and ω mesons at RHIC by PHENIX Yuriy Riabov for the Collaboration
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 2 PHENIX capability to measure ω & Experimental conditions Results: Spectra Integrated Yields Particle Ratios & R AB Mass Peak Shape SummaryOutline
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 3 PHENIX Experiment K+K+ K-K- PHENIX acceptance : -0.35 < < 0.35 2 x 90 o for two arms BBC (vertex) dz = 0.5cm… 2cm BBC (trigger) ε = 50%… 92% DC/PC1 (tracking) dp T /p T ~ 1.0%p T + 0.7% EMC (calorimetric) dE/E ~ 8.1%/√E + 3.0% EMC (t.o.f.) dτ ~ 500 ns EMC (e/π rejection) ~10 EMC (γ-trigger) 0.4GeV… 2.5GeV PC3 (matching) 2-4 mm TOF dτ < 100 ns RICH (e/π rejection) >1000 K + K - BR = 49.2 0.7% e + e - BR = 2.97 0.04 10 -4 e + e - BR = 7.18 0.12 10 -5 0 BR = 8.90 0.25% 0 + - BR = 89.1 0.7%
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 4 PHENIX Experiment e+e+ e-e- ,ω,ω PHENIX acceptance : -0.35 < < 0.35 2 x 90 o for two arms BBC (vertex) dz = 0.5cm… 2cm BBC (trigger) ε = 50%… 92% DC/PC1 (tracking) dp T /p T ~ 1.0%p T + 0.7% EMC (calorimetric) dE/E ~ 8.1%/√E + 3.0% EMC (t.o.f.) dτ ~ 500 ns EMC (e/π rejection) ~10 EMC (γ-trigger) 0.4GeV… 2.5GeV PC3 (matching) 2-4 mm TOF dτ < 100 ns RICH (e/π rejection) >1000 K + K - BR = 49.2 0.7% e + e - BR = 2.97 0.04 10 -4 e + e - BR = 7.18 0.12 10 -5 0 BR = 8.90 0.25% 0 + - BR = 89.1 0.7%
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 5 PHENIX Experiment 00 ω PHENIX acceptance : -0.35 < < 0.35 2 x 90 o for two arms BBC (vertex) dz = 0.5cm… 2cm BBC (trigger) ε = 50%… 92% DC/PC1 (tracking) dp T /p T ~ 1.0%p T + 0.7% EMC (calorimetric) dE/E ~ 8.1%/√E + 3.0% EMC (t.o.f.) dτ ~ 500 ns EMC (e/π rejection) ~10 EMC (γ-trigger) 0.4GeV… 2.5GeV PC3 (matching) 2-4 mm TOF dτ < 100 ns RICH (e/π rejection) >1000 K + K - BR = 49.2 0.7% e + e - BR = 2.97 0.04 10 -4 e + e - BR = 7.18 0.12 10 -5 0 BR = 8.90 0.25% 0 + - BR = 89.1 0.7%
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 6 PHENIX Experiment 00 ω ++ -- PHENIX acceptance : -0.35 < < 0.35 2 x 90 o for two arms BBC (vertex) dz = 0.5cm… 2cm BBC (trigger) ε = 50%… 92% DC/PC1 (tracking) dp T /p T ~ 1.0%p T + 0.7% EMC (calorimetric) dE/E ~ 8.1%/√E + 3.0% EMC (t.o.f.) dτ ~ 500 ns EMC (e/π rejection) ~10 EMC (γ-trigger) 0.4GeV… 2.5GeV PC3 (matching) 2-4 mm TOF dτ < 100 ns RICH (e/π rejection) >1000 K + K - BR = 49.2 0.7% e + e - BR = 2.97 0.04 10 -4 e + e - BR = 7.18 0.12 10 -5 0 BR = 8.90 0.25% 0 + - BR = 89.1 0.7%
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 7 p+pAu+Aud+Au - meson decay modes K + K - d+Au √s NN =200 GeV K + K - Au+Au √s NN =200 GeV e + e - d+Au √s NN =200 GeV e + e - Au+Au √s NN =200 GeV hadronicleptonic PHENIX measures clear signal of K + K - in all collision systems Measurement of e + e - is complicated by combinatorial background
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 8 - meson decay modes p+pAu+Aud+Au 0 + - 0 p+p √s =200 GeV 0 Au+Au √s NN =200 GeV ω e + e - d+Au √s NN =200 GeV ω e + e - Au+Au √s NN =200 GeV ω ω hadronicleptonic PHENIX has first measurement of ω in p+p, d+Au & Au+Au Measurement of ω e + e - is as complicated as for in the same mode η ω
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 9 p+pAu+Aud+Au - meson spectra d+Au √s NN =200 GeV Au+Au √s NN =62 GeV √s NN =200 GeV d+Au √s NN =200 GeV Au+Au √s NN =200 GeV hadronicleptonic PHENIX has a complete set of measurement of K + K - in TOF region First results on e + e - lack statistics.
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 10 ω - meson spectra p+pAu+Aud+Au 0 + - ( 0 ) p+p √s =200 GeV d+Au √s NN =200 GeV 0 Au+Au √s NN =200 GeV ω e + e - Au+Au √s NN =200 GeV ρ, ω, e + e - p+p √s=200 GeV hadronicleptonic PHENIX mapped out high p T ω in p+p, d+Au & produced a first result in Au+Au ω, e + e - in p+p are not ready yet, but the signal there is very clean PHENIX Preliminary nucl-ex/0611031
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 11 - meson yield and temperature hadronicleptonic T approximately the same at√s NN =62, 200 GeV and is constant with N part Yield grows both with √s NN and centrality
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 12 ω/ 0 ratio hadronic PHENIX Run3 PHENIX Run5 ω results in Run3&5 are consistent ω/ π 0 ratio is flat above p T = 2.5 GeV/c both in p+p and d+Au and close to the ratio at lower √s PYTHIA predicts slightly higher value / 0 in p+p Run3 @ √s = 200 GeV = 0.85 ± 0.05(stat) ± 0.09(syst) final / 0 in p+p Run5 @ √s = 200 GeV = 0.81 ± 0.02(stat) ± 0.07(syst) preliminary / 0 in d+Au Run3 @ √s NN = 200 GeV = 0.94 ± 0.08(stat) ± 0.12(syst) final nucl-ex/0611031
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 13 Nuclear Modification Factor ω R AA R cp R ω dA √s NN = 200 GeV (final) MB: 1.03 ± 0.11 ± 0.09 (0%-20%): 0.87±0.18 ± 0.08 R ω AA √s NN = 200 GeV (prelim) Peripheral: 1.11 ± 0.27 MB & 0%-20%: 0.37 ± 0.12 R dA for all light mesons are around 1 R AA for ω & at high p T is below one, same as other mesons Au+Aud+Au nucl-ex/0611031
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 14 p+pAu+Aud+Au Mass peak shape ω STAR: PRL 92, 092301 (2004) All measurements at low p T show agreement with PDG. ω measurements show no evidence of mass modification at high p T nucl-ex/0611031
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 15 HBD for PHENIX e+e+ e-e- ,ω,ω e + e - BR = 2.97 0.04 10 -4 e + e - BR = 7.18 0.12 10 -5 Measurements in di-electron channels are complicated because of the combinatorial background coming from 0 decays. The HBD detector installed in PHENIX in Run 7 vetoes electrons which have close partner to reduce the background. We expect to suppress background level by a factor of ~ 100
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 16 PHENIX measured ω & production in hadronic channels. Both mesons behave consistently with other mesons in different collision systems at different energies. Preliminary results exist on ω & meson production in e + e - decay channel. Current situation needs improvement on the background conditions and more data. The baseline measurements (p+p √s=200GeV) exist in hadronic channels and are being analyzed in leptonic channel using accumulated data. Next major step is to take high statistics and high purity dilepton measurement in d+A and A+A.Summary
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 17
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 18
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 19 ω 0 invariant mass spectra e+pe+C 0 e+p E e =2.8 GeV e+C E e =2.8 GeV Peaks at low masses in the channel may be in part, explained by correlated background from eta, pi0 Ks … CBELSA/TAPS |p |< 500 MeV/c Preliminary shown by V. Metag on Nov.16, 2006 Plenary ref. to D. Trnka (Gießen) priv. com.c PHENIX 0 p+p √s =200 GeV M.Lutz Nucl. Phys. A706 431 (2002) 0 peak Other peaks seen in p+p… Au+Au Correlated background reproduced from the data Part, not all of it!!!
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 20 & K √s NN
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 21 MinBias, dAu, 200 GeV PHENIX preliminary 1/2 m T dN/dm T dy (GeV/c 2 ) -2 dAu KK dAu ee M T (GeV/c 2 )
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 22 KK in pp collisions: Comparison with STAR
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006 23 Comparison of ->K K data Results are self consistent in PHENIX The gap between PHENIX and STAR exist in different energies and systems
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