PaNic02 03/10/02 Hideto En'yo RIKEN/RBRC1 Hideto En’yo RIKEN / RIKEN-BNL Research Center Physics with RHIC Spin Collider ---- just taking off ----- Hideto

PaNic02 03/10/02 Hideto En'yo RIKEN/RBRC 1

Physics with RHIC Spin Collider---- just taking off -----

Hideto En’yo Hideto En’yo

RIKEN / RIKEN-BNL Research CenterRIKEN / RIKEN-BNL Research Center

ContentsContents Status of Spin ColliderStatus of Spin Collider Physics of Spin ColliderPhysics of Spin Collider First Results, HighlightsFirst Results, Highlights Summery & OutlookSummery & Outlook


Polarized Proton Acceleration

KEK OPPPS, Tuned for RHIC at TRIUMPH

500 A, 300 sBooster: No Spin Resonance

Two Rings in the Tunnel

AGS: Partial Siberian Snake

Transfer Lines to RHIC, Spin transparent


Snake Magnet

STARPHENIX

AGSLINAC

RHIC

Proton and its spin motion in Snake4 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


Beam’s View

Si #1

Si #2

Si #4 Si #3

left right

down

up

Si #5

Si #6

Carbon filament target (5mg/cm2) in the RHIC beam

Measure recoil carbon ions at 90º

100 keV < Ecarbon< 1 MeV

Wave-Form Digitizer +FPGA high counting rates (~0.5 MHz)

scaler measurement ~ 310-4 in ~1 minute.

Carbon

ADC values

Arr

ival

tim

e (n

s)

Coulomb Nuclear Interference Polarimeter

STARPHENIX

AGSLINAC

RHIC

PaNic02 K.Kurita


Luminosity in Year 1

0

50

100

150

200

250

300

350

1 3 5 7 9 111315171921232527293133Days into run (from 12/20/01)

STAR 300 nb-1

PHENIX 150 nb-1

Machine Luminosity300 nb-1 /week

Peak 1.8x1030 cm-2s-1


Polarization in Year 1

Yellow Ring Blue Ring


Why polarization was low ?

10% 20% 30%

PAGS

PRHIC

Injection1st Year

Ramp upSpead

SourceImprovement

New AGSSNAKE2004-5

AGS motor generator failure½ ramp up speed2x resonance effect


Prospect of Machine performance

RUN #proton/bunch

[x109]#bunch Beta*

(m)

Emittance

(m)Luminosity

1030 cm-2s-1

Pol.

(%)

2001-

2002

70 55 3 25 1.8 15-25

2002-2003

100 112 1 25 16 45-55

2005- ? 112 1 ? ? 70-80

Design 200 112 1 20 80 70


The Spin Experiments

STARPHENIX

AGSLINAC

RHIC pp2pp

Spin Rotators

pp elastic Silicons in Roman pot-t down (0.004 GeV/c)2

b*=10m (special tune)


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•Parity,CP violating interaction?

•Test of pQCD •Use asymmetries sensitive ONLY to the higher orders (AN at high PT etc.)

?QCD triumph? or

?beyond ?


• ALL: Double Longitudinal Spin Asymmetry– Useful in extracting quark/gluon helicity distributions

)()(

)()(

LLA

ATT: Transversity AN:Twist-3 or TAL:Parity Violation

Asymmetries Measurements


Global QCD Analysis

AAC Pre

liminary

AAC Pre

liminary

M. Hirai, H.Kobayashi, M. Miyama et al.

Impact of RHIC Spin on g With RHIC DATA (1year)


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 A

LZ (~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


Data from the 1st 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


PHENEIX 0 cross section

• Pt Spectrum over 108 magnitude

• NLO pQCD calculation– CTEQ5M pdf

– Potter-Kniehl-Kramer(PKK)

– fragmentation function = pT/2, pT, 2pT

• Consistent with data within the scale dependence.

PHENIX Preliminary

Normalization error of 30% not shown.

MB trigger 2x2 trigger

pT dependent systematic error

Spin02 B.Fox (RBRC)QM02 H,Torii(Kyoto)PaNic02 Y. Goto(RIKEN)


PHENIX J/

µ+µ-e+e-

Br(J/l+l-) (total) = 226 36 (stat.) 79 (syst.) nb

(p+pJ/X) = 3.8 0.6 (stat.) 1.3 (syst.) µbPHENIX Preliminary

Total Cross section vs. the Total Cross section vs. the Color-Evaporation Model predictionColor-Evaporation Model prediction

• CEM Parameters are fixed by fitting low energy data• The result agrees with the CEM prediction at s=200GeV

Spin02 H. Sato( Kyoto) Panic02 K.Ozawa(CNS)

Rapidity distribution compared Rapidity distribution compared with PHITHIA simulationwith PHITHIA simulation


Physics in AN (L-R Asymmetry)useful for local polarimeter for collision point

0 1 2 3 4 5Rapidity

STARFPD

0o CAL

BBC

PHE

NIX

MU

ON

PHE

NIX

CE

NT

RA

L

STA

R T

PCpp2pp

E704 at Fermilab at s=20 GeV, pT=0.5-2.0 GeV/c: XF 0.2 0.4 0.6 0.8PT

Models:: Transversity, Higher Twist,Fragmentation, kT, Orbital. Etc.


STAR Forward rapidity high xF 0 AN

xF ~ E / 100 GeV

STAR FPD Preliminary DataAssuming AN(CNI)= 0.013pT=1.1 - 2.5 GeV/c

0.0

0.2

0.4

-0.20 0.2 0.4 0.6 0.8 1.0

AN

Systematic uncertainty + － 0.05

0 at s 200p p X GeV 0 at s 20p p X GeV Theory predictions

at pT = 1.5 GeV/c

Collins effectAnselmino, et al.PRD 60 (1999) 054027. Sivers effectAnselmino, et al.Phys. Lett. B442 (1998) 470.

Twist 3 effectQiu and Sterman,Phys. Rev. D59 (1998) 014004.

Y.KoikePaNic02

Spin02 G.Rakness(IUCF)


Beam-Beam Counter (BBC)

Luminosity Monitor of STAR

Scintillator annulus installed around the beam

pipe, on the east and west poletips of STAR

magnet at ±3.5m from IR ( 2 < || < 5)

~7m

FPD

BBC (West)

STAR Magnet

+ TPC

BBC (East)

beam pipe

Schematic side view of STAR


STAR BBC

Asymmetry Measured by RHIC polarimeter

BBCAsymmetry

Demonstrate that asymmetry sensitivity better than 1/1000Small since + － cancellation ?

Spin02 J.Kiryluk(UCLA)


12 O‘clock（ local polarimeter for PHENIX)

EM Cal Base

PbWO4

Charge Veto

Neutron VetoHadron Cal Base

Pb

Scintillator

W+Fiber Cal

Post-shower

Spin02 Y.Fukao(Kyoto)Panic02 M.Togawa(Kyoto)

0


12 O’clock


Asymmetries (AN) seen

0 1 2 3 4 5Rapidity

STARFPD

0o CAL

BBC

PHE

NIX

MU

ON

PHE

NIX

CE

NT

RA

L

STA

R T

PC

pp2pp

XF 0.2 0.4 0.6 0.8PT

0

+10 ~ +20%

Charged+1%

Neutron -10%

-3%

0 <3%


Coming Run with longitudinal polarization

3pb-1,P=50%

W. Vogelsang

STAR JET

PHENIX Charged

G will be directly probed

expectations


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 G generates surprises in the data.

• Y2003+, Statistics will be much improved @200GeV, ensuring the determination of G . “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 beyondbeyond…


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

.

Documents

PaNic02 03/10/02 Hideto En'yo RIKEN/RBRC1 Hideto En’yo RIKEN / RIKEN-BNL Research Center Physics with RHIC Spin Collider ---- just taking off ----- Hideto