Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 RHIC Spin Project opening a new era of hadron physics Hideto En’yo RIKEN / RIKEN-BNL Research Center Contents Introduction The Experiments (PHENIX.
Download ReportTranscript Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 RHIC Spin Project opening a new era of hadron physics Hideto En’yo RIKEN / RIKEN-BNL Research Center Contents Introduction The Experiments (PHENIX.
Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 RHIC Spin Project opening a new era of hadron physics Hideto En’yo RIKEN / RIKEN-BNL Research Center Contents Introduction The Experiments (PHENIX detector) Physics Highlights Conclusion Hideto En'yo RIKEN/RBRC 1 ISABELL (abandoned in 1983) to RHIC (started in 2000) 3.83 km circumference Two independent rings 120 bunches/ring 106 ns bunch crossing Can collide ~any nuclei on ~any other nuclei Top Energy: 500 GeV for p-p 200 GeV for Au-Au Luminosity The First Heavy Ion Collider & The first Polarized Collider Au-Au: 2 x 1026 cm-2 s-1 p-p : 2 x 1032 cm-2 s-1 (polarized) Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Year2000 to Year2001 First Collision of Gold beams at 130 GeV/A 10% of Designed Luminosity achieved Successful Physics Run Successful Spin Commissioning! First Collision of Gold beams at 200GeV/A !!! Currently running with Au+Au Beam with ~design luminosity. First Muon Data from PHENIX First Polarized Proton Collision will take place in November – December, 2001! Hideto En'yo RIKEN/RBRC 3 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 RHIC Polarized Collider 70% Polarizati on 32 1 Lmax 2 10 s cm 2 50 s 500 GeV RHIC pC Polarimeters • BRAHMS & PP2PP PHOBOS Absolute Polarimeter (H jet) RHIC PHENIX STAR Spin Rotators 2 1011 Pol. Protons / Bunch e = 20 p mm mrad Partial Siberian Snake KEK Pol. Proton Source 500 mA, 300 ms LINAC Siberian Snakes BOOSTER AGS 200 MeV Polarimeter AGS Internal Polarimeter Rf Dipoles Illustrated by Thomas Roser Hideto En'yo RIKEN/RBRC 4 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 PreRHIC History History to Wedding of HI & SPIN at RHIC • • • • Milestones Naive quark model 1973 Ellis-Jaffe sum rule 1974 Sehgal’s spin crisis 1989 -99 EMC spin crisis S = 1 = Du+Dd+Ds Ds =0 → g1pdx,g1ndx predicted Ds =0 → S 0.58 1 S 0.20.3 , Ds = 0.1 ? Looking for the OTHER spin Carrier 1/2=(1/2)DS+DG+Lq+Lg •1989 RHIC project started •1990 Polarized Collider Workshop at Penn State •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 HI collisions & polarized proton acceleration •2001 The first polarized proton collisions Hideto En'yo RIKEN/RBRC 5 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Spin Structure of Nucleon Parton Distribution Function Du Dd Ds ~ 0.2 1 Quark Distribution D.I.S. q( x, Q 2 ) Unpolarized Distribution Dq( x, Q 2 ) Helicity Distribution q( x, Q 2 ) Transversity Distribution Gluon Distribution g ( x, Q 2 ) 2 Dg ( x, Q ) Hideto En'yo RIKEN/RBRC RHIC 6 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Impact of RHIC Spin on Dg Global QCD Analysis With RHIC DATA (1year) M. Hirai, H.Kobayashi, M. Miyama et al. Hideto En'yo RIKEN/RBRC 7 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 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 – New Structures •Test of pQCD •Use asymmetries sensitive ONLY to the higher orders (AN at high PT etc.) • 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? Hideto En'yo RIKEN/RBRC 8 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 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 Hideto En'yo RIKEN/RBRC 9 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Remarks in the Asymmetry Measurements Asymmetry Measurements 1QQ XN L N L pp ALLexp A LL (x , x ) PB1PB 2 N 1 L2 N L Effect of Background DG ( x1 ) DG ( x2 ) gg Q Q G ( x1 ) G ( x2 ) a LL ｇｇ→ QQ Adata = Asignal [ 1/(1+e) ]+ Aback [e /(1+e) ] Dilution Fake Asymmetry e=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) Hideto En'yo RIKEN/RBRC 10 STAR STAR Acceptance PHENIX Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 PHENIX DETECTOR Central Arms Coverage (E&W) -0.35< y < 0.35 30o <|f |< 120o DM(J/y )= 20MeV DM(g) =160MeV Muon Arms Coverage (N&S) -1.2< |y| <2.3 -p < f < p DM(J/y )=105MeV DM(g) =180MeV West Arm 3 station CSC 5 layer MuID (10X0) p(m)>3GeV/c Globals MVD/BB/ZDC South muon Arm East Arm North muon Arm Hideto En'yo RIKEN/RBRC 12 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 PHENIX Segmentation EM-calorimeter (gift from HI physics) p0gg opening angle 30/25/20/15/10 GeV/c Pt of p0 • Fine segmentation Df<0.01 – finest in the collider history g/p0 separation up to 25GeV • linearity <2% up to 80GeV • Resolution 1.9% 8.2%/E Hideto En'yo RIKEN/RBRC 13 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 MuonArms 3 stations W 5 layer Muon Identifier Double Muon Arm solution is Major Upgrade in PHENIX for SPIN Works as Up-Down counters for mndecay of polarized W Hideto En'yo RIKEN/RBRC 14 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 PHENIX Spin Physics Probes • Measurements with Central Arms – Direct photon – J/ye+e – inclusive high Pt e± p0 inclusive W±e±n Y. Goto (RBRC) A. Vazilevsky(RBRC) N. Saito (RIKEN/RBRC) H. Torii(Kyoto/RIKEN-JRA) • Measurements with Muon Arms – inclusive high Pt m± – Z/g* m+m J/ym+m W±m±n • Measurements with both Arms – cc/bbm±e +X (unlike sign pair) N. Saito (RIKEN/RBRC) H. D.Sato(Kyoto/RIKEN-JRA) N. Hayashi(RIKEN) A. Taketani(RIKEN) K. Kurita (RIKEN) g/leptons penetrating Quark Matter also probe pQCD insite Polarized proton Delivered from RHIC 1-Year Ldt =320/pb at 200GeV 800/pb at 500GeV, (10weeks/y) High polarization ~70% expected ( KEK pol. source ) Y2001: 6 weeks L~1/10 Pol~50% Hideto En'yo RIKEN/RBRC 15 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Jet Production Mixture of gg/gq/qq scatterings Very sensitive to gluon polarization gg gg gq gq DG DG G G Dq DG q G Dq Dq q q qq qq Hideto En'yo RIKEN/RBRC 16 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of DG (gg,gq,qq→p0X) 10 times more yield than g from Gluon Compton Process • convolution of all the partonic asymmetry • Model dependent but DG sensitive from g+q, g+g scatterings • Accessible with 1/10 Luminosity. Y. Goto N.Saito One-Month statistic with full luminosity – Good start for 1st-year physics – Immediate answer if ⊿ｇ is large Hideto En'yo RIKEN/RBRC 17 Measurements of DG (gq→gX) Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 A. Vazilevsky Y. Goto The primary goal of the RHIC spin project • Clean elementary process ALL ( pT ) DG( xg , Q 2 ) G( xg , Q 2 ) A1 ( xq , Q 2 ) aLL (cos * ) p • Background – qq annihilation (~10%, not rejectable) – Bremsstrahlung from jet frangments – Hadronic Decays • Yield 320 pb-1 800 pb-1 Phenix 1-year sensitivity 120K events 1,160K events Hideto En'yo RIKEN/RBRC 18 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Gluon Polarization Sensitivity Y. Goto Decay background ~20% x・DG(x) derived from prompt g measurements only statistical error for; sqrt(s)=200GeV 320pb-1 sqrt(s)=500GeV 800pb-1 crude assumptions as; xg=xT=2pT/sqrt(s) cos(*)0 Convolution over xBJ space and NLO consideration are required. global structure can be seen immediately Hideto En'yo RIKEN/RBRC 19 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of DG ｇｇ→ QQ → em H.D.Sato Kyoto /JSPS • em 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 total cc bb pK Decays pK Decays Hideto En'yo RIKEN/RBRC 20 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of DG ｇｇ→ QQ → (J/y) • Gluon fusion is the major production channel (agreed) • Details are questionable over 20 years. H.D.Sato Kyoto /JSPS Color octet model ALL prediction – Color evaporation – Color octet – Color singlet J/y （color singlet model） – Decay from cc 320pb-1 NJ/y (pT>2GeV)~120k events →ALLJ/y (stat.)~ 0.006 →Error from Back ground ~ 0.001 Precise ALL measurements first to verify the production models bottom Hideto En'yo RIKEN/RBRC pT(mm)>2GeV/c p/K 21 2 GeV/C Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Kinematical Coverage: (x,Q2) • @200GeV Similarly to DIS region • @500GeV Coverage Enlarged! 200GeV γ 200GeV eμ 200GeV e(cc) • Advantageous in Global QCD Analysis! Hideto En'yo RIKEN/RBRC 22 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 N.Saito Weak Boson Detection at PHENIX • W production is Yield in 1-RHIC year at 500GeV – Flavor sensitive – helicity fixed (V-A) Kinematics (realized by N.Saito ) • power of the polarized collider with Muon Endcaps Hideto En'yo RIKEN/RBRC 23 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of Dq, Dq at PHENIX N.Saito Parity violating single Asymmetry unpolarized distribution polarized distribution ALW 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 Hideto En'yo RIKEN/RBRC 24 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Flavor Structure of Nucleon • No reason to assume d = u in nucleon – Dd Du is natural Recent FNAL Data shows 50% difference in p+p/p+d mm(D.Y.) • RHIC – W+/W Yield comparison – p+p then p+He3 ? J.C.Peng,G.T.Garvey d=u PHENIX Wm du PHENIX Wm FNAL-E866 results PRL 80 (1998) 3715 PHENIX We Hideto En'yo RIKEN/RBRC 25 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Searches for New Physics • Anomalous Parity Violation in Jet Production – Contact Interaction (Scale L) • CDF L>1.8 TeV • D0 L>2.4 TeV • RHIC Spin Reach L~3.3 TeV – New Gauge Boson Z’ Hideto En'yo RIKEN/RBRC 26 pC CNI Polarimeter Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 proton Carbon Elastic Scattering • Designed Basing on Successful AGS-E950 Measurement • Installed in Blue Ring – 4 detectors: 45o,135o,225o,315o up Si #3 Si #1 J. Tojo et al. right left Si #2 Si #4 down Hideto En'yo RIKEN/RBRC 27 Polarization with Snake magnet ON/OFF pC CNI Polarimeter Test in AGS E950 & Kyoto Tandem Gg=46.5 Injection energy Snake OFF Vertical polarization Gg=46.5 Injection energy Snake ON Horizontal polarization Gg=48 Acceleration with Snake ON Horizontal polarization Gg=48 Acceleration with Snake OFF Polarization lost up Si #3 Si #1 right left Si #2 down Si #4 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Conclusions • RHIC Spin program is very unique. • Y2000 Polarized proton commissioning was very successful. • Y2001, The first measurements of helicity asymmetry will SOON be performed @200GeV. Sizable DG generates surprises in the High pT p0 , High pT m , J/y data. • Y2002+, Statistics will be much improved @200GeV, ensuring the determination of DG in direct g and e-m 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 beyond… Hideto En'yo RIKEN/RBRC 29 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 L and E Upgrades • Luminosity Upgrades: 25 Times – 8 Times by Ion Source – 3 Times by increasing number of bunches: • 120 bunches 360 bunches • 106 nsec bunch spacing to 35.3 nsec • Energy Upgrades: 500 GeV 650 GeV – RHIC Dipoles: 30% Margin – RHIC DX Magnets: 10% Margin – With DX Magnet Upgrade, 650 GeV Collision is possible Hideto En'yo RIKEN/RBRC 30 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of DG (gq→gX) Background reduction segmenttation p0gisolategmerged prompt g +decay g mass reconstruction p0 isolation cut R=0.4, E-fraction=5% Hideto En'yo RIKEN/RBRC 31 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Measurements of DG ｇｇ QQ (μsingle) 2GeV/c charm 4106 ALL 10-3 bottom 4106 ALL 10-3 pTmin • Large statistics but with significant background bb is 0.7mb in PYTHIA < a few mb expected • Source of background H.D.Sato Kyoto /JRA 4GeV/c 6104 0.01 2105 410-3 6GeV/c 2103 0.05 2104 0.015 – Decays before Central Magnet – Punch-through hadrons – g+g, g+q dominant – ALL fake ~ ALL signal p→m • Background evaluation – 5 layer MuID for punch through estimation – Decay muon control with vertex position c→m Asymmetry may well be sizable Good exercise for the 1st year run Hideto En'yo RIKEN/RBRC 320pb-1 b→m 32 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Drell-Yan in PHENIX Dq 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 Hideto En'yo RIKEN/RBRC FNAL E886 33 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 em coincidence in PHENIX H.D.Sato Kyoto/RIKEN-JRA x1 x2 Central Arm x1P ｂ→m ｂ→e P x2P ALLpp→bbＸ μ ALL Muon Arm GS-A e GS-B GS-C Hideto En'yo RIKEN/RBRC Mem(GeV) 34 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 World Competition of Dg/g(x) RHIC Spin is THE BEST MEASUREMENT among currently running experiments, even only with 1EXPT&1 CHANNEL. Hideto En'yo RIKEN/RBRC GS-C 35 Italy-Japan Symposium on Heavy Ion Physics 26/Sep/01 Channel PHENIX DG sensitivity at a glance 500GeV 200GeV 800/pb 320/pb xregion stat g (Pt>10GeV) 0.040.15 1100k xregion typical ALL errors background stat 0.010.3 110k DG/G~4% 20-30% bremsh, g merging wide 500k A LL <0.1% gg,gq,qq mixed up p 0 (Pt>5GeV) wide 5M bb/cc →m bb/cc →e J/y→mm J/y→ee cc→em bb→em ~0.2 vs ~0.03 8M 4M cc,4M bb hadron decays study on going <0.01 120k A LL <1% 6%(b-decays) 0.01-0.05 120k study on going ~0.2 vs ~0.03 100k A LL <1% hadronic decays S/N~2 ~0.2 vs ~0.03 120k A LL <1% hadronic decays S/N~6 High Statistic Probes (1st year + later detail studies) Cleaner Probes (2nd Year and later) Global approach to DG from many probes available Hideto En'yo RIKEN/RBRC 36