Yuriy Riabov QM2006 Shanghai Nov.19, 2006 1 Measurement of the leptonic and Measurement of the leptonic and hadronic decays of hadronic decays of and and ω ω mesons at RHIC by PHENIX mesons at RHIC by PHENIX Yuriy Riabov Yuriy Riabov for the Collaboration for the Collaboration
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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
1
Measurement of the leptonic and Measurement of the leptonic and hadronic decays of hadronic decays of and and ωω mesons at RHIC by PHENIXmesons at RHIC by PHENIX
PHENIX mapped out high pT 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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- meson yield and temperature- meson yield and temperatureh
adro
ni
cle
pto
ni
c
T approximately the same at√sNN=62, 200 GeV and is constant with Npart
Yield grows both with √sNN and centrality
Yuriy Riabov QM2006 Shanghai Nov.19, 2006
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ωω//00 ratioratioh
adro
ni
cPHENIX Run3
PHENIX Run5
ω results in Run3&5 are consistentω/π0 ratio is flat above pT = 2.5 GeV/cboth 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
RdA for all light mesons are around 1RAA for ω & at high pT is below one, same as other mesons
Au+Aud+Au
nucl-ex/0611031
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p+p Au+Aud+AuMass peak shapeMass peak shape
ωSTAR: PRL 92, 092301 (2004)
All measurements at low pT show agreement with PDG.ω measurements show no evidence of mass modification at high pT
nucl-ex/0611031
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HBD for PHENIXHBD for PHENIX
e+
e-
,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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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.
SummarySummary
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006
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Yuriy Riabov QM2006 Shanghai Nov.19, 2006
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ωω 00 invariant mass spectra invariant mass spectrae+p e+C
0 e+p Ee =2.8 GeV e+C Ee =2.8 GeV
Peaks at low masses in the channel may be in part , explained by correlated background from eta, pi0 Ks …
CB
EL
SA
/T
AP
S
|p|< 500 MeV/c |p|< 500 MeV/c
Pre
lim
ina
ry s
ho
wn
by
V.
Me
tag
on
No
v.1
6,
20
06
P
len
ary
ref.
to
D.
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ka
(G
ieß
en
) p
riv
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om
.c
PH
EN
IX
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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& K& K√sNN
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MinBias, dAu, 200 GeV
PHENIX preliminary1/2
mT d
N/d
mTd
y (G
eV
/c2)-
2
dAuKK
dAuee
MT(GeV/c2)
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KK in pp collisions: Comparison with STAR
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Comparison of ->KK data
Results are self consistent in PHENIX
The gap between PHENIX and STAR exist in different energies and systems