Transcript Experiments at RHIC, the First Spin Collider ---- just taking off ----Hideto En’yo RIKEN / RIKEN-BNL Research Center CCAST/RBRC Symposium, April 2003.

Experiments at RHIC, the First Spin Collider
---- just taking off ----Hideto En’yo
RIKEN / RIKEN-BNL Research Center
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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Tin Toy
How this toy works ?
A Fly Wheel is working hard inside,
which carries the moment of inertia
Tires rotating, and runs
Spin of the Earth and Spin of Proton
Spin Top and Magnet characters
Fundamental Questions
What attracts quarks
What is the fly wheel of Proton
How can we study ?
What is the fly wheel
in the proton
1
J
2
Proton Spin Crisis
Polarize protons ( arrange all the proton
spin to the
axis )high
Accelerate
to same
the very
energy
And Collide !
Spin collider
【The first in the world】
What We learn ?
Particle
Hadron Physics
Physics
=Physics @ RICH
ＱＧＰ
Proton Structure
Nuclear Physics
Astro Physics
The First
Element,
0.0001sec
after
the Big-Bang
QuarkNucleon
Gluon Plasma
Yuko Mochizuki, RIKEN-RARF
Long Island, USA、NY
RHIC
Circumference 3.83 km
Two rings
– Proton + Proton
– Nucleus + Nucleus
不死鳥PHENIX 検出器
西・電子・光子測定器
南μ介子測定器
北μ介子測定器
東・電子・光子測定器
PHENIX Experiment
How we can polarize proton
Polarized Proton
Acceleration
KEK OPPPS,
Tuned for RHIC at
Two Rings in the Tunnel
Booster:
No Spin Resonance
TRIUMPH
Transfer Lines to RHIC,
Spin transparent
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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AGS: Partial Siberian Snake
Snake Magnet
4 Helical Dipoles – one Snake
essential invention for RHIC spin
Proton and its spin motion in Snake
2 Snakes in each ring
Snake axis orthogonal each other
Spin is preserved up to 250GeV
RHIC
PHENIX
RIKEN fund
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
100 keV < Ecarbon< 1 MeV
up
Si #6
q~90º
Wave-Form Digitizer +FPGA
high counting rates (~0.5 MHz)
scaler measurement  de ~
310-4 in ~1 minute.
Si #1
Carbon
left
Si #5
Si #4
Si #2
right
Si #3
down ADC values
Beam’s View
RHIC
PHENIX
STAR
LINAC
AGS
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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Luminosity in Year 1
PHENIX 150 nb-1
Machine
Luminosity
300 nb-1 /week
Peak 1.8x1030 cm2s-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)
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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Polarization in Year 1
Yellow Ring
Blue Ring
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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Why polarization was low ?
PRHIC
Source
Improvement
New AGS
SNAKE
2004-5
Ramp up
Spead
10%
20%
30%
Injection
1st Year
PAGS
AGS motor generator failure
½ ramp up speed
2x resonance effect
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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２００３
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Prospect of Machine performance
RUN
20012002
20022003
20042005
Design
#proton
/bunch #bunch
[x109]
Beta*
(m)
Emittanc Luminosity
e
1030 cm-2s-1
(pmm)
Pol.
(%)
70
55
3
25
1.8
15-25
100
112
1
25
16
45-55
?
112
1
?
?
70-80
200
112
1
20
80
70
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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The Spin Experiments
Spin Rotators
RHIC
PHENIX
STAR
pp2pp
pp elastic
Silicons in Roman pot
-t down (0.004 GeV/c)2
b*=10m (special tune)
LINAC
AGS
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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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 •NEW TOOL to study hadronic
• h1: transversity processes
•W,Z @500GeV
•flavor sensitive studies
on the structure
functions
?QCD triumph?
•cc/bb
or
•Production mechanism
?beyond ?
•Spin in the fragmentation
•Parity,CP violating
CCAST/RBRC Symposium, April 2003. Hideto
En'yo
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interaction?
Asymmetries Measurements
• ALL: Double Longitudinal Spin
Asymmetry
– Useful in extracting quark/gluon helicity
distributions
 ()   ()
ALL 
 ()   ()
AL:Parity Violation ATT: Transversity
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
CCAST/RBRC Symposium, April 2003. Hideto En'yo
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
5
1
2
Models:: Transversity, Higher Twist,
Fragmentation,
Orbital.
Etc.
CCAST/RBRCkT,
Symposium,
April
2003. Hideto En'yo
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4
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
predictions
p p 
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
PaNic02
xF ~CCAST/RBRC
E / 100Symposium,
GeV April 2003.
Hideto En'yo
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Beam-Beam Counter (luminosity monitor)
PHENIX-BBC
|AN| ~ 1%
: 3.0 – 5.0
PHENIX-BBC
|AN| < 0.3%
: 3.0 - 3.9
PHENIX preliminary
(backward)
Asymmetry Measured
by
CCAST/RBRC Symposium, April 2003.
RHIC polarimeter
Hideto En'yo
(forward)
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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
p
0
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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
5
1
2
Charged
+1%
3
4
Neutron 10%
g -3%
p0 <3%
Rapidity
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expectations
Coming Run with
longitudinal polarization
3pb-1,P=50%
W. Vogelsang
PHENIX Charged
STAR JET
DG will be
directly
CCAST/RBRC
Symposium, probed
April 2003. Hideto En'yo
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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.Vorgelsang 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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