The RHIC Beam Energy Scan Program: Results from the PHENIX Experiment
Status of PHENIX Experiment
description
Transcript of Status of PHENIX Experiment
K. Ozawa (University of Tokyo)
University of Tokyo, Tsukuba University,
Hiroshima University, KEK, Waseda
University, Nagasaki Institute of Applied
Science
The project is associated with study of hot and dense nuclear matter generated by high energy heavy ion collisions.
Relativistic Heavy Ion Collider (RHIC) and PHENIX detector system are constructed at Brookhaven National Laboratory (BNL).
Japan-US collaboration works effectively in every steps of the experiment.
Huge number of events are acquired in recent 10 years and many measurements suggest formation of Quark-Gluon-Plasma.
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Observe Quark-Gluon-Plasma
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Study of quarkdeconfinement
Phase transition of “QCD vacuum”
In ordinary matter, quarks are confined.
QGP is a quark de-confined state.
It can be reproduced and studied by RHIC.
Create high temperature matter.
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High Energy Heavy Ion collisions at RHIC.
Au-Au @ sNN = 200 GeV
Measure matter properties
RHIC
PHENIXInitial Energy Density / TemperatureThermalization and thermal parametersQuark Degree-of-Freedom of the matter Quark de-confinementOrder parameter of the chiral symmetry
Construction• Done by 2004
Operation• Costs• Man Power
Calibration• Electron
Identification• Time of Flight• Trigger &
Luminosity• Reaction Plane
Physics Analysis• ~ 3 Dr thesis per
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AGEL RXPD
TOFRICHBBC
Magnet
coils
Japanese Detectors in PHENIX
Since June 2000, whole PHENIX detectors including Japanese detectors are well operated and huge statistics are obtained
With Run4 and run7 integrated luminosity, several measurements are achieved.• v2 of identified particles, Jet energy loss, J/ suppression
Further physics results can be obtained with Run 10 data.
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PHENIX Year Species s1/2 [GeV ] Ldt Ntot (sampled) Data Size
Run3 2002/03 d-Au 200 2.74 nb-1 5.5 G 46 TB
Run4 2003/04 Au-Au 200 241 b-1 1.5 G 270 TB
Run-7 2007 Au-Au 200 813 b-1 5.1 G 650 TB
Run-8 2008 d-Au 200 80 nb-1 160G 3.8 PB
Run-10 2010 Au-Au 200 1300 b-1 8.2 G 1.0 PB
88 papers published to date• 8 papers are submitted
citations extremely impressive• 4 250+ top cite paper• 20 100+ top cite paper• + 28 50+ top cite paper
PHENIX White paper (Nucl.Phys. A757,184, 2005)• 2nd most cited nucl-ex paper in 2007• Total 829 citations
Most cited paper, with 503 citations is“Suppression of hadrons with large transverse momentum in
central Au+Au collisions at s(NN)**(1/2) = 130-GeV”Adcox, et al., PRL 88, 022301 (2002)
(Dr thesis, K. Oyama, University of Tokyo)
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Measuring high pT particle yields:• Initial yields and pT distributions can
be predicted from p+p measurements + pQCD + cold nuclear effects
• Deviations can be attributed to the medium formed in A+A collisions
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A+A
ddpNdT
ddpNdpR
TNN
AA
TAA
TAA /
/)(
2
2
dNg/dy = 1000( 30 ~ 50 x Nucleus )dNg/dy = 1000( 30 ~ 50 x Nucleus )
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Angle correlation caused by Jet
Correlation is disappeared in Au+Au
○proton●Au+Au
Big step between SPS and RHIC
Angle correlationCollision Energy
Dep.
Particle species Dep.
Particles are not interactedConserve initial isotropy
Medium is formed & Thermalized Geometry creates
anisotropy
Measurements of anisotropic particle emission
Large anisotropy
Early Thermalize
Anisotropic flow of 7Li atom gas
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Quark number scaling
Measurement of Melting T
TJ/ = 2.0Tc
J/Melting
Color ScreeningAnisotropy is scaled by the number of constituent quark in meson and baryon
KET: Kinetic Transverse Energy (ET – M0)Mass difference is corrected
meson follows other mesons.Note: M ~ Mp
Color Screening
cc
If Rforce ~ Rscreening < Rbind, qq is never bound.Only with de-confinement
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Hydro + J/T. Gunji et al. PRC 76:051901,2007
QGP
Enough Initial Energy and TemperatureHigh gluon density matter is formedThermalization is achievedDirect evidence of de-confinement
Evidences for creation of Quark Gluon Plasma
Suggests
s
4Predicted limit
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Measurements of /s
Relation with AdS/CFT
Based on flow and charm measurements
Press Release in Japan
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J
Correlated
DD
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De-confinement (J/ suppression)
Charm, bottom quark in QGP
Chiral symmetry via
Thermal photon via lepton pair
PLB670, 310(2009)
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p+p NORMALIZED TO mee<100 MeV
Clear enhancement is observed in the Clear enhancement is observed in the mass region below mass region below ..
arXiv:0706.3034
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Black Line• Baseline calculations
Colored lines• Several models
Low mass M>0.4GeV/c2:
• some calculations OK M<0.4GeV/c2:
not reproduced• Mass modification• Thermal Radiation
No model can reproduce experimental data at this moment.
No model can reproduce experimental data at this moment.
arXiv:0706.3034
Both statistical and systematic errors depend on huge background caused by Dalitz decays and conversions
Both statistical and systematic errors depend on huge background caused by Dalitz decays and conversions
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• One gas volume
– Same gas for Radiator and detection
– CF4 (γ th ~ 28)
• Window less Cerenkov conter
• CsI photo casode
– UV sensitive (6 eV, 200nm)
signal electron
Cherenkov blobs
partner positronneeded for rejection
e+
e-
pair openingangle
~ 1 m
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~20 pe
few pe
Hadron
Single electron
Projected Performance @ Run10
Rejection factor
Np.e. of single electron
Luminosity [unit of Run4 ]
1.4 /nb recordedimproves effective statistics by ≥ 35
Signal significance
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• p+p (Run5) result with * method agrees with NLO pQCD predictions, and with statistical method at high pT
– Confirmation of the method
• For Au+Au (Run4), there is a significant low pT excess above p+p expectations– Interpreted as thermal
emission -> Initial T
Direct Photon arXiv:0804.4168
To be published in PRL
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We have a press release at APS spring meeting.
Our experiment is introduced as a hottest science experiment on the planet!
Our experiment is introduced as a hottest science experiment on the planet!
We need to explore QCD nature
RHIC can explore the region below using collision energy scan.
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QCD Phase Transition In QCD phase diagram, critical point is important, since the point can determine the absolute scale.
The project is associated with study of hot and dense nuclear matter to observe Quark-Gluon-Plasma and investigate its properties.
For this purpose, Relativistic Heavy Ion Collider (RHIC) and PHENIX detector system are constructed at Brookhaven National Laboratory (BNL).
Huge number of events are acquired in recent 10 years and many measurements suggest generation of Quark-Gluon-Plasma.
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As a signal of chiral symmetry restoration• Measure vector mesons.• Mass shift or modification is
expected. Lepton decays become good probes.
• Not interacting “strongly.” Current results has poor statistics due
to large background
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R. Rapp (Nucl. Phys A661(1999) 238c
Au+Au
e+ e -
e+ e -
Background Rejection with new detector
Installed in 2009 Fully operated in 2010 run
Also, long data acquisition is expected in 2010
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Direct photonDirect photon• Directly emitted from Directly emitted from
the medium the medium Not from hadronNot from hadron
• Hard photonHard photon Initial pQCDInitial pQCD
• Thermal photonThermal photon Hadron gasHadron gas QGPQGP
Turbide, Rapp, Gale, Phys. Rev. C 69 (014903), 2004
Window for thermal photons from QGP in this calculation: Window for thermal photons from QGP in this calculation: ppTT = 1 - 3 GeV/ = 1 - 3 GeV/cc
pQCD calculation should be confirmed in High ppQCD calculation should be confirmed in High pTT region region
After subtraction of large After subtraction of large background from hadron background from hadron decays, decays,
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