Latest results of nucleon spin structure measurements from PHENIX RIKEN/RBRC Itaru Nakagawa 1

The Relativistic Heavy Ion Collider accelerator complex at Brookhaven National Laboratory PHENIX STAR Brahms pp2pp 2

RHIC p+p accelerator complex 3 v vv BRAHMS & PP2PP STAR PHENIX AGS LINAC BOOSTER Pol. Proton Source Spin Rotators 20% Snake Siberian Snakes 200 MeV polarimeter Rf Dipoles RHIC pC “CNI” polarimeters PHOBOS RHIC absolute pH polarimeter Siberian Snakes AGS pC “CNI” polarimeter 5% Snake Coulomb-Nuclear Interference

PHENIX Experiment 4 Pioneering High Energy Nuclear Interaction EXperiment

13 Countries; 70 Institutions Abilene Christian University, Abilene, TX 79699, U.S. Baruch College, CUNY, New York City, NY , U.S. Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY , U.S. Physics Department, Brookhaven National Laboratory, Upton, NY , U.S. University of California - Riverside, Riverside, CA 92521, U.S. University of Colorado, Boulder, CO 80309, U.S. Columbia University, New York, NY and Nevis Laboratories, Irvington, NY 10533, U.S. Florida Institute of Technology, Melbourne, FL 32901, U.S. Florida State University, Tallahassee, FL 32306, U.S. Georgia State University, Atlanta, GA 30303, U.S. University of Illinois at Urbana-Champaign, Urbana, IL 61801, U.S. Iowa State University, Ames, IA 50011, U.S. Lawrence Livermore National Laboratory, Livermore, CA 94550, U.S. Los Alamos National Laboratory, Los Alamos, NM 87545, U.S. University of Maryland, College Park, MD 20742, U.S. Department of Physics, University of Massachusetts, Amherst, MA , U.S. Morgan State University, Baltimore, MD 21251, U.S. Muhlenberg College, Allentown, PA , U.S. University of New Mexico, Albuquerque, NM 87131, U.S. New Mexico State University, Las Cruces, NM 88003, U.S. Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S. Department of Physics and Astronomy, Ohio University, Athens, OH 45701, U.S. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY , U.S. Chemistry Department, Stony Brook University,SUNY, Stony Brook, NY , U.S. Department of Physics and Astronomy, Stony Brook University, SUNY, Stony Brook, NY 11794, U.S. University of Tennessee, Knoxville, TN 37996, U.S. Vanderbilt University, Nashville, TN 37235, U.S. Universidade de São Paulo, Instituto de Física, Caixa Postal 66318, São Paulo CEP , Brazil Institute of Physics, Academia Sinica, Taipei 11529, Taiwan China Institute of Atomic Energy (CIAE), Beijing, People's Republic of China Peking University, Beijing, People's Republic of China Charles University, Ovocnytrh 5, Praha 1, , Prague, Czech Republic Czech Technical University, Zikova 4, Prague 6, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, Prague 8, Czech Republic Helsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI Jyväskylä, Finland Dapnia, CEA Saclay, F-91191, Gif-sur-Yvette, France Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, France Laboratoire de Physique Corpusculaire (LPC), Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, Aubiere Cedex, France IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, France Debrecen University, H-4010 Debrecen, Egyetem tér 1, Hungary ELTE, Eötvös Loránd University, H Budapest, Pázmány P. s. 1/A, Hungary KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, Hungary Department of Physics, Banaras Hindu University, Varanasi , India Bhabha Atomic Research Centre, Bombay , India Weizmann Institute, Rehovot 76100, Israel Center for Nuclear Study, Graduate School of Science, University of Tokyo, Hongo, Bunkyo, Tokyo , Japan Hiroshima University, Kagamiyama, Higashi-Hiroshima , Japan KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki , Japan Kyoto University, Kyoto , Japan Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki , Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama , Japan Physics Department, Rikkyo University, Nishi-Ikebukuro, Toshima, Tokyo , Japan Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo , Japan Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, Japan Chonbuk National University, Jeonju, Korea Ewha Womans University, Seoul , Korea Hanyang University, Seoul , Korea KAERI, Cyclotron Application Laboratory, Seoul, South Korea Korea University, Seoul, , Korea Myongji University, Yongin, Kyonggido , Korea Department of Physocs and Astronomy, Seoul National University, Seoul, South Korea Yonsei University, IPAP, Seoul , Korea IHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, , Russia INR_RAS, Institute for Nuclear Research of the Russian Academy of Sciences, prospekt 60-letiya Oktyabrya 7a, Moscow , Russia Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia Russian Research Center "Kurchatov Institute", Moscow, Russia PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, , Russia Saint Petersburg State Polytechnic University, St. Petersburg, Russia Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Vorob'evy Gory, Moscow , Russia Department of Physics, Lund University, Box 118, SE Lund, Sweden Feb

6 PHENIX detector Global detectors –beam-beam counter (BBC), zero-degree calorimeter (ZDC) Minimum-bias trigger Luminosity measurement Local polarimeter Philosophy –high resolution at the cost of acceptance –high rate capable DAQ –excellent trigger capability for rare events Central Arms –|  | < 0.35,  =  2×2 –Momentum and energy measurement, particle-ID –Detecting electron, photon, hadron –Small amount of material to reduce conversion background Muon Arms –1.2 < |  | < 2.4 –Momentum measurement and muon-ID –Hadron absorber (muon piston)

 G DOUBLE HELICITY A LL RESULTS 7 ProbeAdvantage 00 Statistics  Different fragmentation  0 -  0 correlation Kinematic constraint charged  G sign heavy flavor decay e - Lower x, g-g dominant MPC clusterLower x

PDFs from Asymmetries 8 Example: o Choose channel with high statistics: p + p → π 0 + X o Complicated mixture of amplitudes, changes as a function of kinematics. o How does one extract ΔG from the experimentally determined: o Requires calculational techniques based on factorization.

Factorization 9 Δf a,b = polarized quark and gluon distribution functions Δ Δ Δ D h f = fragmentation function for Partonic cross section from pQCD

10 Polarized gluon distribution (I) Central Rapidity 00 00 Phys. Rev. D83, (2011) Abundant Statistics Sensitive to sign of  g  0,  +/-   Different fragmentation

11 Polarized gluon distribution (II) Central + Forward Rapidity, Low Energy Phys. Rev. D87, (2013) Single e High purity of glue-glue subprocess sensitive to small-x  Forward Cluster Small x ~  0 at  s = 62.4 GeV Phys. Rev. D79, (2009) High x

12 Extraction of Gluon Polarization Quark Strangeness Gluon Anti-quark QCD Global Fit DISSIDISpp PHENIX STAR (2005,2006) HERMES COMPASS Jlab… RHIC data constrain on gluon polarization!

13 QCD global analysis Interpretation DSSV++ (with latest results) First Positive Polarization  G Result :

SEA QUARK POLARIZATION PRELIMINARY A L W FROM RUN12 14 ProbeRapidityAdvantage W->ecentralGood S/N W->  forwardEnhanced sea quark

W-Boson √s = 500 GeV 15  Parity Violation Asymmetry Clean flavor separation w/o fragmentation uncertainty

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Single e,  P T Spectra 17 W->e + (Mid Rapidity) W+BG BG only W->  + (Forward Rapidity) Signal Background P T [GeV/c] S/B ~ 1/3  Background estimation in data driven manner  Resolution Improvement for better S/N in progress  Background estimation in data driven manner  Resolution Improvement for better S/N in progress

W-boson Asymmetry (Run12) 18 Poor knowledge of Sea quark Polarization Wide rapidity coverage Boxes are systematic uncertainties from background Run 2012 Beam Polarization uncertainty  P/P = 3.4% (not shown)

W measurement Run13 Projections 19 Existing data + Run13 Data Delivered Luminosity RHIC white paper Existing data

TRANSVERSE SINGLE SPIN ASYMMETRY A N 20 ProbeRapidityAdvantage p0, etacentralGood S/N MPC ClusterforwardEnhanced sea quark neutronVery Forward

Transverse structure of the nucleon 21 Single transverse-spin asymmetry –Expected to be small in hard scattering at high energies FNAL-E704 –Unexpected large asymmetry found in the forward-rapidity region –Development of many models based on perturbative QCD p p

Transverse-spin physics For establishment of TMD and higher-twist approach – Single transverse-spin asymmetry (SSA) of inclusive hadrons – Sivers effect Sivers distribution function (initial state) – transverse-momentum dependence of partons inside the transversely-polarized nucleon – Collins effect Transversity distribution (initial state) – correlation between transversely-polarized nucleon and transversely-polarized partons inside Collins fragmentation function (final state) – Higher-twist effect quark-gluon & multi-gluon correlation 22 SPSP k T,p p p SPSP p p SqSq kT,πkT,π Sivers effect Collins effect Inclusive  0

Transverse-spin physics 23 Forward EM cluster at  s = 200 GeV no decrese at high p T expected from higher-twist effect constrains gluon Sivers effect arXiv: To be published from PRD Midrapidity  0 and 

neutron BBC hits Very Forward Neutron 24 large negative asymmetry used for local polarimetry! Phys. Rev. D88, (2013) Single pion exchange?

3-dimensional nucleon structure Nucleon structure beyond the simple parton picture Many-body correlation of partons –To describe the orbital motion inside the nucleon Parton distribution in transverse direction –Extended/generalized picture of the parton distribution –Transverse-momentum dependence (TMD) –Space distribution (tomography) 25 Phenomenological model with GPD data Lattice QCD calculation

MPC-EX upgrade MPC (Muon Piston Calorimeter) –Electromagnetic calorimeter MPC-EX –Preshower detector –Commissioning in 2014 –Experiment in < |  | < 3.8 –Installed in the muon piston Direct photon asymmetry –To distinguish the Sivers effect and the higher-twist effect Collins asymmetry in jets –  0 correlation with jet-like clusters 26 MPC MPC- EX 49pb -1, P=0.6 Twist-3 p+p prediction SIDIS (TMD) p+p prediction Phys Rev. D (2011) arXiv v1 (2012) ANAN xFxF Charged clusters with >=3 tracks, single-track  0 ’s

sPHENIX upgrade sPHENIX – Barrel upgrade – Forward upgrade – Partial installation and commissioning in – Completion and experiment in Barrel upgrade baseline – Compact jet detector – Using upgraded RHIC accelerator – For precision measurement of jet, dijet, photon-jet correlation to understand the nature of QGP Barrel upgrade extension – Additional tracking layers – Preshower detector – For heavy-flavor and internal jet structure measurements 27

sPHENIX forward upgrade Open geometry – Wide kinematic coverage of photon, jet, leptons and identified hadrons Compatible design for eRHIC detector (ePHENIX) – Constraint from IR design of eRHIC (|z| < 4.5m) – Hermeticity for exclusive measurements 28 GEM Station4 HCal GEM Station2 z (cm) R (cm) HCal η~1 η~4 η~-1 R (cm) Silicon Station1 MuID RICH GEM Station3 Aerogel

twist 3 Fit of SIDIS SIDIS old  s = 200 GeV y=3.3 jets sPHENIX forward upgrade Sivers effect in Drell-Yan process –Valence quark region at x  0.2 with 1 <  < 4 coverage Jet asymmetry –Sivers effect or higher-twist effect Asymmetry inside of jets –Collins effect 29 jet  h+X

Summary Origin of the nucleon spin 1/2 –Gluon-spin contribution A L First non-zero positive gluon polarization by pQCD fit on Run9 data –Sea-quark contribution Wide rapidity coverage. Sensitive to sea quark polarization at forward Understanding of transverse-spin phenomena –Sivers effect / Collins effect / higher-twist effect –3-dimensional nucleon structure –Many-body correlation of partons A N measurements The forward sPHENIX upgrades toward understanding of the 3-dimensional nucleon structure –Polarized Drell-Yan measurement / jet asymmetry and asymmetry inside of jets –Evolution to ePHENIX toward electron-proton collisions at eRHIC 30

BACKUP 31

Run11 Central Arm W->e 32 Backgrounds could be mitigated by relative isolation cut Run9 PRL106, (2011) Signal electron : High momentum electron Isolated

Single Electron P T Spectra 33 Background Dominant Signal + Background Signal Background Power Law Counting Background Shape Fixed in 10<P T <20 GeV/c Jacobian Peak (PYTHIA+GEANT) + Power Low Background Fitting Resulting Background contamination 14 ~ 17%. Run11

Forward W->  Analysis 34

Single Muon P T Spectra 35  Efficiency corrections  W/Z cross section employed RHICBOS NLO  S/B estimation from fixed W/Z cross section (RHICBOS NLO) S/B ~ 1/3  Background estimation in data driven manner  Resolution Improvement for better S/N  Background estimation in data driven manner  Resolution Improvement for better S/N

The First Forward A L W Results 36 More to come! First Forward W Asymmetry Results!

References 37 [1]

Global Fit including Run9  0 A LL 38 By S.Taneja et al (DIS2011) ala DSSV with slightly different uncertainty evaluation approach DSSV DSSV + PHENIX Run9  0 A LL No node … Uncertainties decreased A node at x~0.1 ?

Charged pion Cross Section 39 Charge separated fragmentation functions are not well constrained in DSS FFs In good agreement with STAR

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HBD Analysis for Heavy Flavor Decay e - 41

HBD Signal Occupancy 42

 G Extraction from A LL HFe 43  Open charm production dominates in p T range of 0.50 < pT < 1.25 GeV/c (J/ψ <2%, b quark<5%)  pQCD prediction for A LL open charm obtained from CTEQ6M PDFs + PYTHYA + LO hard scattering cross section  A LL open charm ~|∆g/g(x, µ)| 2  |∆g(x, µ)| = C g(x, µ) is assumed  Results: |∆g/g(logx,µ)| 2 <3.3 ×10 −2 (1σ) and 10.9 ×10 −2 (3σ)

Central W Analysis 44

Central Arm A L 45

The PHENIX Detector Philosophy – high resolution & high-rate at the cost of acceptance – trigger for rare events Central Arms – |  | < 0.35,  ~  – Momentum, Energy, PID Muon Arms – 1.2 < |  | < 2.4 – Momentum (MuTr) Muon Piston Calorimeter – 3.1 < |  | < h+h+   ,0,0  MPC

Further Sea Quark Measurement w/ DY 47 ϒ-states J/Ψ Drell Yan charm beauty Invariant mass (GeV) S/B contributions w/o vertex detector High-mass DY Extract DY events from heavy flavors using FVTX