Transcript Physics with RHIC Spin Collider ---- just taking off ----Hideto En’yo RIKEN / RIKEN-BNL Research Center Contents  Status of Spin Collider  Physics of.

Physics with RHIC Spin Collider
---- just taking off ----Hideto En’yo
RIKEN / RIKEN-BNL Research Center
Contents
 Status of Spin Collider
 Physics of Spin Collider
 First Results, Highlights
 Summery & Outlook
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Polarized Proton Acceleration
Two Rings in the Tunnel
KEK OPPPS,
Tuned for RHIC at TRIUMPH
500 mA, 300 ms
AGS: Partial Siberian Snake
Booster: No Spin Resonance
Transfer Lines to RHIC, Spin transparent
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Snake Magnet
4 Helical Dipoles – one Snake
essential invention for RHIC spin
2 Snakes in each ring
Snake axis orthogonal each other
Spin is preserved up to 250GeV
RIKEN fund
Proton and its spin motion in Snake
RHIC
PHENIX
STAR
LINAC
AGS
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PaNic02 K.Kurita
Coulomb Nuclear Interference Polarimeter
Carbon filament target (5mg/cm2) in
the RHIC beam
Measure recoil carbon ions at q~90º
100 keV < Ecarbon< 1 MeV
Wave-Form Digitizer +FPGA
high counting rates (~0.5 MHz)
scaler measurement  de ~ 310-4
in ~1 minute.
up
Si #6
left Si #5
Si #4
Si #1
Carbon
Si #2
right
Si #3
down ADC values
Beam’s View
RHIC
PHENIX
STAR
LINAC
AGS
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Luminosity in Year 1
PHENIX 150 nb-1
Machine Luminosity
300 nb-1 /week
Peak 1.8x1030 cm-2s-1
350
300
250
STAR
300 nb-1
200
150
100
50
0
1 3 5 7 9 111315171921232527293133
Days into run (from 12/20/01)
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Polarization in Year 1
Yellow Ring
Blue Ring
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Why polarization was low ?
PRHIC
Source
Improvement
New AGS
SNAKE
2004-5
Ramp up
Spead
10%
20%
Injection
1st Year
30%
PAGS
AGS motor generator failure
½ ramp up speed
2x resonance effect
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Prospect of Machine performance
RUN
20012002
20022003
2005Design
#proton/
bunch
[x109]
#bunch
70
Emittance
(pmm)
Luminosity
55
Beta*
(m)
3
25
1.8
Pol.
(%)
15-25
100
112
1
25
16
45-55
?
112
1
?
?
70-80
200
112
1
20
80
70
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1030 cm-2s-1
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The Spin Experiments
Spin Rotators
RHIC
PHENIX
pp2pp
STAR
pp elastic
Silicons in Roman pot
-t down (0.004 GeV/c)2
b*=10m (special tune)
LINAC
AGS
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Spin Physics at RHIC
RHIC = polarized parton collider
• Spin Structure of Nucleon
– 1/2=(1/2)DS+DG+Lq+Lg
 DG: gluon polarization
 Dq: Anti-quark polarization
•Test of pQCD
•Use asymmetries
sensitive ONLY to
the higher orders (AN
at high PT etc.)
– New Structures
• h1: transversity
?QCD triumph?
or
?beyond ?
•NEW TOOL to study hadronic
processes
•W,Z @500GeV
•flavor sensitive studies on
the structure functions
•cc/bb
•Production mechanism
•Spin in the fragmentation
•Parity,CP violating interaction?
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Asymmetries Measurements
• ALL: Double Longitudinal Spin Asymmetry
– Useful in extracting quark/gluon helicity distributions
 ()   ()
ALL 
 ()   ()
AL:Parity Violation ATT: Transversity
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AN:Twist-3 or T
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Impact of RHIC Spin on Dg
Global QCD
Analysis
With RHIC
DATA (1year)
M. Hirai, H.Kobayashi, M. Miyama et al.
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Measurements of Dq, Dq at PHENIX
N.Saito
Parity violating single Asymmetry
unpolarized distribution  polarized distribution
W
L
A
Du( xa , MW2 )d ( xb , MW2 )  Dd ( xa , MW2 )u( xb , MW2 )

u( xa , MW2 )d ( xb , MW2 )  d ( xa , MW2 )u( xb , MW2 )
– d small at high x Du/u (Dd/d for W)
flavor selected valence quark polarization
 Dd/d (Du/u for W) determination
Major background is Z decay (20%)
systematic error will be minimized (~1%)
with ALZ (~20%)and (Z) measurements
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Data from the
st
1
polarized pp runs
 Run all the time with vertical polarization
polarization is too low to perform double spin
No gluon information
 Commission the detectors for polarized pp
 Cross section reference for pp and AA
 First measurements of L-R asymmetry at
root s = 200GeV
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Spin02 B.Fox (RBRC)
QM02 H,Torii(Kyoto)
PaNic02 Y. Goto(RIKEN)
PHENIX Preliminary
PHENEIX
p0 cross section
• Pt Spectrum over 108 magnitude
• NLO pQCD calculation
–
–
–
–
CTEQ5M pdf
Potter-Kniehl-Kramer(PKK)
fragmentation function
m = pT/2, pT, 2pT
• Consistent with data within the scale
dependence.
Normalization error
of 30% not shown.
pT dependent systematic error
MB trigger
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2x2 trigger
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PHENIX J/
Rapidity distribution compared
with PHITHIA simulation
µ+µ-
Total Cross section vs. the
Color-Evaporation Model prediction
e+e-
Br(J/l+l-) (total) = 226  36 (stat.)  79 (syst.) nb

Spin02 H. Sato( Kyoto)
Panic02 K.Ozawa(CNS)
(p+pJ/X) = 3.8  0.6 (stat.)  1.3 (syst.) µb
•
•
CEM Parameters are fixed by fitting low energy data
The result agrees with the CEM prediction at s=200GeV
PHENIX Preliminary
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Physics in AN (L-R Asymmetry)
useful for local polarimeter for collision point
E704 at Fermilab
at s=20 GeV, pT=0.5-2.0 GeV/c:
PT
XF
0.2
0.4 0.6 0.8
PHENIX MUON
STAR TPC
PHENIX CENTRAL
STAR
FPD
pp2pp
BBC
0o CAL
0
1
Models:: Transversity, Higher Twist,
Fragmentation,
Orbital.
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3
4
5
Rapidity
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Spin02 G.Rakness(IUCF)
STAR Forward rapidity high x
AN p
p p  p 0 X at s  200GeV
0.4 STAR FPD Preliminary Data
Assuming AN(CNI)= 0.013
pT=1.1 - 2.5 GeV/c
F
p0 AN
Theory
p p predictions
 p 0 X at s  20GeV
at pT = 1.5 GeV/c
Collins effect
Anselmino, et al.
PRD 60 (1999) 054027.
Sivers effect
0.2
Anselmino, et al.
Phys. Lett. B442 (1998) 470.
Twist 3 effect
0.0
Qiu and Sterman,
Phys. Rev. D59 (1998) 014004.
Systematic uncertainty +－ 0.05
0.2 0.4 0.6
0.8 1.0
-0.20
Y.Koike
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Beam-Beam Counter (BBC)
Luminosity Monitor of STAR
Scintillator annulus installed around the beam
beam pipe
pipe, on the east and west poletips of STAR
magnet at ±3.5m from IR ( 2 < |h| < 5)
~7m
STAR Magnet
FPD
BBC
(East)
+ TPC
BBC
(West)
Schematic side view of STAR
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Spin02 J.Kiryluk(UCLA)
STAR BBC
Demonstrate that asymmetry sensitivity better than 1/1000
Small since p+ p－ cancellation ?
BBC
Asymmetry
Asymmetry
Measured by RHIC polarimeter
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Spin02 Y.Fukao(Kyoto)
Panic02 M.Togawa(Kyoto)
12 O‘clock
（local polarimeter for PHENIX)
Hadron Cal Base
Neutron Veto
Post-shower Scintillator
EM Cal Base
Pb
Charge Veto
PbWO4
W+Fiber Cal
p0
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12 O’clock
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Asymmetries (AN) seen
PT
XF
0.2
0.4 0.6 0.8
PHENIX MUON
STAR TPC
PHENIX CENTRAL
p0
+10 ~ +20%
STAR
FPD
pp2pp
BBC
0o CAL
0
1
2
3
Charged
Neutron -10%
g -3%
p0 <3%
4
5
Rapidity
+1%
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expectations
Coming Run with
longitudinal polarization
3pb-1,P=50%
W. Vogelsang
PHENIX Charged
STAR JET
DG will be
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Summary and Outlook
• RHIC spin program has begun. We have a series of program over 5
years to go.
• Y2001-2, The first polarized proton collision was successfully done
with transversely polarized beam, produced unexpected spin phenomena
which may relate to unknown behavior of QCD (transversity etc)
• Y2002-3, The first measurements of helicity asymmetry will SOON be
performed @200GeV. Sizable DG generates surprises in the data.
• Y2003+, Statistics will be much improved @200GeV, ensuring the
determination of DG . “Spin Crisis” will hopefully be solved by then.
• Y2005+, 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 beyond…
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Many Thanks To
• RHIC Spin Collaboration (Spokesman: G. Bunce)
Spin physics is an integral part of the goals of the STAR, PHENIX and pp2pp experiments.
• RHIC Accelerator Spin Group (Spokesman: T.Roser, Project Manager: W.Mackay)
• RIKEN and RIKEN/BNL Research Center (Group Leaders: H. En’yo, G.Bunce,
N. Saito), Theory Group （W.Forgelsang et.al.)
• STAR Spin Physics Working Group (Conveners: L. Bland, G. Eppley)
• PHENIX Spin Physics Working Group (Conveners: Y. Goto, M. Perdekamp)
• pp2pp Experiment (Spokesman: W. Guryn)
• BNL Groups: RHIC Spin Group (Group Leader: G. Bunce);
• KEK Accelerator Group (Y. Mori et al.);
• Laboratory / University participation
Kyoto-U, TITech, ANL, IUCF, KEK and many others
.
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