3-Nov-99 Hideto En'yo, Kyoto University 1
PHENIX for the First Spin Collider,RHIC Hideto En’yo Hideto En’yo Kyoto UniversityKyoto University
for the PHENIX collaborationfor the PHENIX collaboration
ContentsContents Introduction (how we are here)Introduction (how we are here) PHENIX detectorPHENIX detector Physics HighlightsPhysics Highlights SummarySummary (time table towards discovery)(time table towards discovery)
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Spin Physics at RHIC
• Spin Structure of Nucleon– 1/2=(1/2)+G+Lq+Lg
G: gluon polarization q: Anti-quark polarization
– New Structures• h1: transversity
RHIC = polarized parton colliderRHIC = polarized parton collider
•NEW TOOL to study hadronic processes
•W,Z @500GeV•flavor sensitive studies on the structure functions
•cc/bb•Production mechanism
•Spin in the fragmentation
•Test of pQCD •Use asymmetries sensitive ONLY to the higher orders (AN at high PT etc.)
?QCD triumph? or
?beyond ?
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Milestones• Naive quark model = 1 = u+d+s• 1973 Ellis-Jaffe sum rule s =0 g1
pdx,g1ndx predicted
• 1974 Sehgal’s spin crisis s =0 • 1989 -99 EMC spin crisis s = 0.1
•RHIC project started •1990 Polarized Collider Workshop at Penn State •1991 FNAL proposal (gg c2 ...turned down…)•1992 STAR and then PHENIX, approved for RHIC •1993 RHIC-Spin proposal (Accelerator,STAR,PHENIX)•1995 RIKEN-BNL MoU [Spin construction started]•1997 RIKEN-BNL Research Center established (T.D.Lee)•2000 The first polarized proton collider REALIZED
Looking for the OTHER spin Carrier1/2=(1/2)+G+Lq+Lg
Pre-RHICHistory
History toWedding ofHI & SPINat RHIC
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Yesterday’s PHENIX
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PHENIX COLLABORATIONMcGill University, Montreal, Quebec, Canada University of Muenster, Muenster, Germany Myong Ji University,Yongin City 449-728, Korea Nagasaki Institute of Applied Science, Nagasaki, Japan
University of New Mexico, Albuquerque, New Mexico, USA New Mexico State University, Las Cruces, New Mexico, USA Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, USAPNPI: St. Petersburg Nuclear Physics Institute,Leningrad,Russia RIKEN, Institute for Physical and Chemical Research, Japan University of California - Riverside (UCR), Riverside, USA University of Sao Paolo, Sao Paolo, Brazil State University of New York - Stony Brook, Stony Brook,USA University of Tennessee (UT), Knoxville, TN 37996, USA University of Tokyo, Bunkyo-ku, Tokyo 113, Japan Tokyo Institute of Technology, Ohokayama, Tokyo, Japan University of Tsukuba, Tsukuba, Japan Vanderbilt University, Nashville, TN 37235, USA Waseda University, Tokyo, Japan Weizmann Institute, Rehovot, Israel Yonsei University, Seoul 120-749, KOREA
University of Alabama,Huntsville, Alabama, USA Banaras Hindu University, Banaras, India Bhabha Atomic Research Centre (BARC),Bombay, India Brookhaven National Laboratory (BNL), Upton, NY USAChina Institute of Atomic Energy (CIAE), Beijing, P. R. China Columbia University, ... Nevis Laboratories, Irvington, USA Center for Nuclear Study, University of Tokyo, Tokyo,Japan Florida State University (FSU), Tallahassee, FL 32306, USA Georgia State University (GSU), Atlanta, GA, 30303, USA Hiroshima University, Higashi-Hiroshima 739, Japan Institute of High Energy Physics, Protovino, Russia Iowa State University (ISU) and Ames Laboratory, Ames, USAJoint Institute for Nuclear Research,Dubna, Russia KEK, Institute for High Energy Physics,Tsukuba, Japan Korea University, Seoul, 136-701, Korea Kurchatov Institute,Moscow, Russia Kyoto University, Kyoto, Japan LANL: Los Alamos National Laboratory, LosAlamos, NM,USALLNL: Lawrence Livermore National Laboratory, USA Lund University, Lund, Sweden
41institutions=15 USA +2 American-Continent+7 Europe+17India-Asia (10 Japan)430 scientists and engineers
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PHENIX DETECTOR
South muon Arm
North muon Arm
West Arm
East Arm
Central ArmsCoverage (E&W) -0.35< y < 0.35 30o <||< 120o
M(J/)= 20MeVM() =160MeV
Muon ArmsCoverage (N&S) -1.2< |y| <2.3 - < <M(J/)=105MeVM() =180MeV
3 station CSC5 layer MuID (10X0)p()>3GeV/c
GlobalsMVD/BB/ZDC
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EM-calorimeter (gift from HI physics)
PreliminaryPreliminary
AGS data & CERN data 1.9% 8.2%/E
AGS data CERN data
PreliminaryPreliminary
• Fine segmentation <0.01 – finest in the collider history separation up to 25GeV
• linearity <2% up to 80GeV • Resolution 1.9% 8.2%/E
30/25/20/15/10 GeV/c Pt of opening angle
PHENIX Segmentation
See A. Vazilevsky(RBRC) talk
H.Torii,Y.Goto,N.Saito
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MuonArms
Double Muon Arm solution is Major Upgrade in PHENIX for SPINWorks as Up-Down counters for -decay of polarized W
South Muon Magnet was buit in Kobe just after the disaster
W
3 stations
5 layer Muon Identifier
• 1.1<||<2.4,
• absorber~10λint
• pz cut~2GeV/c
• hadron rejection <210-3
Δp/p~3% (@3~10GeV/c)
~106MeV/c2
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• Measurements with Central Arms– Direct photon inclusive 0
– J/e+eW±e±– inclusive high Pt e±
• Measurements with Muon Arms– inclusive high Pt ± J/+
– Z/* + W±±• Measurements with both Arms
– cc/bb±e+X (unlike sign pair)
leptons penetrating Quark Matter also probe pQCD insite Delivered from RHIC accelerator complex
1-Year Ldt =320/pb at 200GeV 800/pb at 500GeV, (10weeks/y) High polarization ~70% expected ( KEK pol. source )
PHENIX Spin Physics Probes
Y. Goto (RBRC)A. Vazilevsky(RBRC)N. Saito (RIKEN/RBRC)H. Torii(Kyoto/RIKEN-JRA)
N. Saito (RIKEN/RBRC)H. D.Sato(Kyoto/RIKEN-JRA)N. Hayashi(RIKEN)A. Taketani(RIKEN)K. Kurita (RIKEN)
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Asymmetry Measurements
Effect of Background
data = Asignal [ 1/(1+) ]+ Aback [ /(1+) ]
=Nback/Nsignal
Keys Luminocity (STATISTIC !) Polarization (>70% expected at RHIC) Large Partonic Asymmetry (Choose good channel) Low Background (Clean signal and/or clean analysis) Low Background Asymmetry (better measured within the same experiment)
General Remarks in the Asymmetry Measurements
LNLN
LNLN
PPA
BBLL
21
1exp
gg QQ
Dilution Fake Asymmetry
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Measurements of G (gqX)
The primary goal of the RHIC spin project
• Clean elementary process
• Background– qq annihilation (~10%, not rejectable)
– Bremsstrahlung from jet frangments
– Hadronic Decays
• YieldPhenix1-yearsensitivity
)(cos),(),(
),()( *2
12
2
LLqp
g
gTLL aQxA
QxG
QxGpA
320 pb-1 800 pb-1
120K events 1,160K events
A. VazilevskyY. Goto
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• PYTHIA Simulation– PYTHIA5.7/JETSET7.4
– PDFLIB GRV94LO• factor ~2 lower (K-factor)
– Gehrmann-Stirling 95 • NLO pol-PDF
• assume u=d,=s• almost No constraint on G
• Integrated Luminosity• sqrt(s)=200GeV 320pb-1
• sqrt(s)=500GeV 800pb-1
Simulation
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• Background reduction– segmenttation
0isolatemerged
– prompt +decay – mass reconstruction 0
– isolation cut • R=0.4, E-fraction=5% See A. Vazilevsky’s talk
A. VazilevskyY. Goto Measurements of G (gqX)
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• x ・ G(x) derived from prompt measurements– only statistical error for;
• sqrt(s)=200GeV 320pb-1
• sqrt(s)=500GeV 800pb-1
– crude assumptions as;• xg=xT=2pT/sqrt(s)
• cos(
Convolution over xBJ space and NLO consideration are required.
global structure can be seen immediately
Gluon Polarization SensitivityGluon Polarization Sensitivity Y. Goto
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10 times more yield than fromGluon Compton Process
• convolution of all the partonic asymmetry
• Model dependent but G sensitive from g+q, g+g scatterings
• Accessible with 1/10 Luminosity.
– Good candidate for 1st-year physics
Measurements of G (gg,gq,qqX)
One-Month statisticwith full luminocity
Y. GotoN.Saito
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Measurements of Ggg QQ (μsingle)
• Large statistics but with significant background bb is 0.7b in PYTHIA < a few b expected
• Source of background – Decays before Central Magnet– Punch-through hadrons– g+g, g+q dominant– ALL fake ~ ALL signal
• Background evaluation – 5 layer MuID for punch through estim
ation– Decay muon control with vertex positi
on
Asymmetry may well be sizableGood exercise for the 1st year run
b→
320pb-1
c→
→
pTmin 2GeV/c 4GeV/c 6GeV/c
charmALL
4106
10-36104
0.012103
0.05bottomALL
4106
10-32105
410-32104
0.015
H.D.SatoKyoto /JRA
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Measurements of Ggg QQ (J/)
• Gluon fusion is the major production channel (agreed)
• Details are questionable over 20 years.– Color evaporation– Color octet – Color singlet
– Decay from c
pT()>2GeV/c
bottom
J/ ( color singlet model )
/K
320pb-1
H.D.SatoKyoto /JRA
NJ/ (pT>2GeV)~120k events
→ALLJ/ (stat.)~ 0.006
→Error from Back ground ~ 0.001Precise ALL measurements
first to verify the production models
GeV/C2
Color octet modelALL prediction
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Measurements of G gg QQ e
• e coincidence enhance the leptons from heavy quarks
• 320/pb provides 120k bb,100k cc,100k hadronic decays
• Like sign pair (also includes signal from bb) gives fine estimation for the background effects
KK DecaysDecays
KK DecaysDecays
bb
cc
total
H.D.SatoKyoto /JRA
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PHENIX G sensitivity at a glance
Channel typical
ALL errors background
xregion stat xregion stat
Pt>10GeV 1100k 110k G/G~4% 20-30% bremsh, merging
(Pt>5GeV) wide 5M wide 500k ALL<0. gg,gq,qq mixed up
bb/cc→ ~0.2 vs ~0.03 8M 4M cc,4M bb hadron decays
bb/cc→ e study on going
J→ <0.01 120k ALL< 6%(b-decays)
J→ ee 0.01-0.05 120k study on going
cc→ e ~0.2 vs ~0.03 100k ALL< hadronic decays S/N~2
bb→ e ~0.2 vs ~0.03 120k ALL< hadronic decays S/N~6
500GeV
800/pb
200GeV
320/pb
High Statistic Probes (1st year + later detail studies)Cleaner Probes (2nd Year and later) Global approach to G from many probes available
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Weak Boson Detection at PHENIX• W production is
– Flavor sensitive
– helicity fixed (V-A)
Kinematics (realized by N.Saito )
• power of the polarized collider with Muon Endcaps
N.Saito
Yield in 1-RHIC year at 500GeV
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Measurements of q, q at PHENIX
– d small at high x u/u (d/d for W) flavor selected valence quark polarization
d/d (u/u for W) determination
Major background is Z decay (20%)
systematic error will be minimized (~1%) with AL
Z (~20%)and (Z) measurements
N.Saito
Au x M d x M d x M u x M
u x M d x M d x M u x MLW a W b W a W b W
a W b W a W b W
( , ) ( , ) ( , ) ( , )
( , ) ( , ) ( , ) ( , )
2 2 2 2
2 2 2 2
Parity violating single Asymmetry unpolarized distribution polarized distribution
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Flavor Structure of Nucleon• No reason to assume d = u in nucleon
– d u is natural • RHIC
– W+/W Yield comparison– p+p then p+He3 ?
FNAL-E866 resultsPRL 80 (1998) 3715
J.C.Peng,G.T.Garvey
PHENIX We
PHENIX WPHENIX W
d=u du
Recent FNAL Data shows 50% difference in p+p/p+d (D.Y.)
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Conclusions (Time Table towards discovery)• PHENIX construction on going
– Y2000 Spring E&W Central Arms ready for the first Au-Au collisions– Y2000 Summer South Muon Arm ready for the first polarized collisions– Y2001 Summer North Muon Arm ready for the 500GeV running
• PHENIX High rate capability• PHENIX Powerful particle IDs for pQCD probes
• Y2001, The first measurements of helicity asymmetry will be performed @200GeV. Sizable G generates surprises in the High pT 0 , High pT Jdata.
• Y2002, Statistics will be much improved @200GeV, ensuring the determination of G in direct and e- coincidence data. “Spin Crisis” will hopefully be solved by them.
• Y200?, Weak Bosons will be produced at RHIC, the NEW “flavor sensitive” tool for the anti-quark/quark polarization and unpolarized structure function of anti-quark measurements.
• And beyondbeyond…
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• Following view graphs are for backups
Following view graphs are for backups
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Drell-Yan in PHENIX
FNAL E886
q measurements ALL
h1 measurements ATT
Statistics are not great at high mass (>10GeV)where listed amplitude will be sizable. (not well studied yet)un-polarized structure function is not well determined ( revealed by the FNAL data)p+He3 might be the way to go @200GeV x1 0.1-0.5 vs x20.001-0.01
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Measurements of G (gqX)
• Background reduction– segmentation
0isolatemerged
– prompt +decay – mass reconstruction 0
– isolation cut • R=0.4, E-fraction=5%
See A. Vazilevsky’s talk
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 5 10 1 5 20 2 5 30 3 5 40
0 - merged
0 - separated in accept.
Bremsstrahlung
Other photons
A. VazilevskyY. Goto
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x1 x2
x1P
CentralArm
Muon Arm
x2P
Pb→ e
b→
e coincidence in PHENIX
ALLpp→bb X
GS-A
GS-B
GS-C
AL
L
μe
Me(GeV)
H.D.SatoKyoto/RIKEN-JRA
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• Lead-scintillator sampling calorimeter (PbSc)– WLS fiber readout
– 66 layers of Pb 1.5mm + Sc 4mm
– laser monitoring system
– 1 super-module = 12 x 12 towers
• Lead glass calorimeter (PbGl)– LED monitoring system
– 1 super-module = 4 x 6 towers
PbSc PbGlSize(cm x cm) 5.52 x 5.52 4.0 x 4.0
Depth(cm) 37.5 40Number of towers 15552 9216Sampling fraction ~ 20% 100%
cov. 0.7 0.7 cov. 90+45deg 45deg/ mod 0.011 0.008 / mod 0.011 0.008
X0 18 14.4Molière Radius ~ 3cm 3.68cm
PbSc 1 module (4 towers)
PbGl 1 tower
PHENIX EM-CalorimeterPHENIX EM-Calorimeter
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Japanese Factory
BNL FactoryInstallation Completed in Time: Sep ’98
•MuID Mechanics installed•Tracking Chambers in produciton
MuID construction
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Oct. 1998 West Arm
Sep. 1999 East Arm
PHENIX Central ArmPHENIX Central Arm
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