Spin Physics at PHENIX Douglas Fields University of New Mexico For the PHENIX Collaboration

Spin Physics at PHENIX

Douglas Fields

University of New Mexico

For the PHENIX Collaboration

Douglas Fields, University of New Mexico, for the PHENIX Collaboration

2

Outline

• Brief Motivation• Polarized Proton Program at RHIC• PHENIX Capabilities

o Centralo Forward

• PHENIX Present and Upcoming Results o Double-Longitudinal Spin Asymmetrieso Single-Longitudinal Spin Asymmetrieso Transverse Spin Asymmetries

• Future of PHENIX• Summary

7/11/2013

[C.L., Pasquini, Vanderhaeghen (2011)][C.L., Pasquini (2011)]

Motivation - Parton Distributions

Wigner distributions

TMDs

GPDs

PDFs

FFs

e.g. DVCS

e.g. SIDISDIS

elastic scattering

GTMDs

IPDsTDs

???

Longitudinal

Transverse

2D Fourier

transform

[Miller (2007)][Carlson, Vanderhaeghen (2008)][Alexandrou et al. (2009,2010)]

[Burkardt (2000,2003)]

Alessandro’s « elephant »

Slide stolen from Cédric Lorcé’s Transversity 2011 talk.


4

Motivation - Moments

• I won’t foray into the debate on spin decomposition.• Suffice to say that the proton is very complicated theoretically

(or at least computationally) and is difficult to explore experimentally.

• The best approach then, is to attempt to measure everything possible, and let the results lead the theorists to sort it all out.

• The PHENIX experiment can contribute to:o The knowledge of ΔG through the double-longitudinal asymmetries in various channels.o The understanding of ΔΣ (antiquark) through single-longitudinal parity violating

asymmetries in W production.o The understanding of δq and L (OAM) through single-transverse asymmetries and

through other means.

1 1ΔΣ Δ

2 2p q GS G L L

7/11/2013


5

PDFs from Asymmetries

7/11/2013

• Example:o Choose channel with high statistics:

p + p → π0 + Xo 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.

gqgq G

G

q

q

qqqq q

q

q

q

gggg G

G

G

G

1LL

B Y

N N R N NA

P P N N R N N


6

Factorization

7/11/2013

,

ˆ a bf f fX hLL a b f

a b

f f D

f h z

Δfa,b = polarized quark and gluon distribution functions

Δ

Δ

Δ Dhf = fragmentation

function for

Partonic cross section from pQCD


7

Factorization

7/11/2013

• A final state that can be produced from q-g or g-g scattering will contain Δg in its factorization

• Factorization allows a global analysis to input a measured ALL to extract Δg(x).

• Will need some evidence that factorization works.

1 2

1 2

1 2

1 2

1 2

1 2

ˆ

ˆ

f f fX hf

f f fLL f f fX h

ff f f

f f DA

f f D


8

RHIC Spin• The polarized pp

program at RHIC is a tremendously complicated project and its operation should be considered a great technical achievement.

• There have been issues that have frustrated us as consumers of luminosity, but we have managed to get close to our goals.

7/11/2013

BRAHMS & PP2PP

STAR

AGS

LINAC BOOSTER

Pol. H- Source

Spin Rotators(longitudinal polarization)

Solenoid Partial Siberian Snake

Siberian Snakes

200 MeV Polarimeter

AGS Internal Polarimeter

Rf Dipole

RHIC pC PolarimetersAbsolute Polarimeter (H jet)

AGS pC PolarimetersStrong AGS Snake

Helical Partial Siberian Snake

PHOBOS

Spin Rotators(longitudinal polarization)

Spin flipper

Siberian Snakes

PHENIX


9

RHIC Spin• Polarized p+p

Sqrt(s) collisions at 62.4 GeV, 200 GeV and 500 GeV

• Recent Spin Runs:o 2009: first 500 GeV

polarized running (longitudinal)

o 2011, 2012: 510 GeV polarized running (longitudinal and transverse).

o 2013: 510 GeV polarized running (longitudinal only)

7/11/2013


10

PHENIX Experiment

7/11/2013

• Began as a shotgun marriage of several collaborations, but has become a fruitful multi-purpose experiment.

• Central spectrometers focus on electrons and photons.

• Forward spectrometers focus on muons.

• Specialty in triggering for rare physics.


11

PHENIX Central Spectrometers

7/11/2013

• 2 arms: |η|<0.35, each = /2• Electromagnetic Calorimeter (EMCal: PbSc, PbGl) with fine segmentation Δφ x Δη ~ 0.01 x 0.01: triggering• Drift Chamber (DC) and Pad Chamber (PC): tracking charged tracks and charge separation• VTX detector (commissioned in 2011)

Good photon trigger =>

g

g

p0


12

PHENIX Central Spectrometers

7/11/2013

• 2 arms: |η|<0.35, each = /2• Electromagnetic Calorimeter (EMCal: PbSc, PbGl) with fine segmentation Δφ x Δη ~ 0.01 x 0.01: triggering• Drift Chamber (DC) and Pad Chamber (PC): tracking charged tracks and charge separation• VTX detector (commissioned in 2011)

Good electron trigger =>

e


13

PHENIX Forward Spectrometers

7/11/2013

• 1.2 < η < 2.4 (North) -2.2 < η <-1.2 (South), = 2 • Muon Tracker (MuTr): tracking, triggering• Muon Identifier (MuID): particle ID, triggering• Resistive Plate Chamber (RPC): particle ID, triggering• FVTX silicon tracker for opening angle determination, track matching, displaced vertex and isolation cuts

m+

m-

J/Ψ

Good di-muon trigger =>


14

PHENIX Forward Spectrometers

7/11/2013

• 1.2 < η < 2.4 (North) -2.2 < η <-1.2 (South), = 2 • Muon Tracker (MuTr): tracking, triggering• Muon Identifier (MuID): particle ID, triggering• Resistive Plate Chamber (RPC): particle ID, triggering• FVTX silicon tracker for opening angle determination, track matching, displaced vertex and isolation cuts

m

W

Good high p muon trigger =>


15

ALLπ0 Mid-rapidity

7/11/2013

• The most abundant probe at PHENIX, triggered using electromagnetic calorimeter

• π0 → γγ BR ~ 98.8 %• Well developed method over the

years• Sensitive to gluon polarization in

leading order• Reconstruct invariant mass from

photons in calorimeter and identify pion counts

• Combinatorial background determined from sidebands

• Asymmetry is corrected for background

√s = 200 GeV

Partonic contributions


16

Cross-sections

7/11/2013

200 GeV, π0, mid-rapidity

500 GeV, π0, mid-rapidity

200 GeV, h, mid-rapidity

• NLO (or better) cross sections show good agreement to measured values, giving confidence in partonic cross-section determination for asymmetries.


17

ALLπ0 Mid-rapidity

7/11/2013

• PHENIX has published data from 200 GeV 2005 and 2006 runs, and has preliminary from the 2009 run and the combined data.

• The 500 GeV 2012 and 2013 runs will be forthcoming.


18

Relative Luminosity

7/11/2013

• However, the central arm π0 ALL is systematics limited up to pT = 4 GeV/c

• Limits constraining power on ΔG.

• Understanding/reducing this systematic will increase impact of PHENIX ALL results.

Rel Lumi Systematic Uncert. 1.4 x 10-3


19

ALLπ+/- and ALL

η Mid-rapidity

7/11/2013

• While these channels are currently statistics limited, with the new, higher statistics data set coming, they can provide sensitivity to:o Charged pions are sensitive to the sign of ΔGo Eta provides a good test for s fragmentation functions


20

From ALL to G (with GRSV model)

7/11/2013

arXiv:0810.0694

Compare ALL data to curves (produce 2 vs G)

1.0:error.expSyst. )3(2.0and)1(1.02.04:errorStat. 2.0

8.022]3.0,02.0[

GeVG x

GRSV

Generate g(x) curves for different (with DIS refit)

1

0)( dxxgG

Calculate ALL for each G


21

DSSV++ ΔG From RHIC Data

7/11/2013

• Very large uncertainty at lower x which may bring ΔG to big value

• Need forward rapidity• But ALL expected to be

small there • Minimizing systematic

top priority


22

Bjorken-x sensitivity at Forward Rapidity

7/11/2013

<xg>~0.01 for π0 <xg>~0.001 for π0- π0


23

MPC Cluster ALL

7/11/2013

Cluster Decomposition

• Since, at these very forward rapidities, the two photons from the π0s merge, we can, instead, look at clusters as π0 surrogates.

• Cluster composition is dominated by them (~80%).


24

Forward Di-Hadrons

7/11/2013

• MPC electronics upgrade has been functional for Runs 12 and 13• Now have ability to trigger on di-hadrons

– At 500 GeV, this gives gluon-x sensitivity at the 10-3 scale– Would (will) be very exciting to make a big dent here…


25

Challenging Measurement at Low-x

7/11/2013

• The asymmetry is expected to be O(10-4) in the forward measurements• The relative luminosity uncertainty is O(10-3) • Statistical uncertainty for run9 is O(10-3) • On disk already: FOM 50x greater than run9, so new stat error will be O(10-4) • To better constrain ΔG at low-x, the relative luminosity must improve, but historically is has worsened (multiple collisions).

max signal expected

Run, s syst

2005, 200 2.5x10-4

2006, 200 7.5x10-4

2009, 200 14x10-4

Relative Luminosity Syst Error History


26

Relative Luminosity• Currently, the collaboration is working diligently to reduce the

uncertainty on the relative luminosity.• Our approach is to measure high statistics (scalars) from

several different detectors in different kinematic regions.• In the past, we have only had information from the BBC and

the ZDC. • Residual effects (vertex profile, multiple collisions, residual

asymmetries, etc.) have been difficult to sort at the 10-4 level.• We now have a FVTX scaler which is sensitive to multiple

collisions and the vertex profile in a way which should help to understand these residual effects and reduce the relative luminosity uncertainty.

7/11/2013


27

Impact on ΔΣ

7/11/2013

Phys. Rev. D 80, 034030 (2009)DSSV Global Analysis:

)ΔΔΔΔΔ(ΔΔ sdusdudx

Sea anti-quark polarization not well constrained in polarized SIDIS

SIDIS results depend on large-uncertainty fragmentation functions

1 1ΔΣ Δ

2 2p q GS G L L


28

W Production

7/11/2013

p

p

Wdu Wud

No fragmentation involved - Ws detected through their leptonic decay channels

Ws couple directly to the quarks and antiquarks of interest

Due to parity violation, perfect quark/antiquark helicity separation: only left-handed quarks and right-handed anti-quarks are selected

PHENIX exploits maximal-parity violation in W ± boson production in longitudinally polarized p+p collisions


29

W Production

7/11/2013

p

p

Wdu Wud

Parity Violating Longitudinal Single-Spin Asymmetry:

For : and probedW u d For : and probedu dW

)()()()(

)()()()(

2121

2121

xuxdxdxu

xuxdxdxuAW

L

Flipping the spin orientation of one of the colliding protons and

averaging over another :

LLLL

)()(

)()(1

NN

NN

PAW

L


30

Simulated Impact

7/11/2013

DSSV global analysis

DSSV global analysis

+ simulated 200 pb−1

W ± AL at proton-proton collisions in RHIC

Phys. Rev. D 81, 094020 (2010)

Significant impact for reducing uncertainties


31

W± in PHENIX Central

7/11/2013

eWpp

e

B

|η|<0.35

Detect high energy e± :• Trigger: EMCal 4x4 Tower Sum (fully efficient above 12 GeV)• High energy EMCal clusters matched to charged tracks in DC for charge determination (Δϕ < 0.01 rad)

Isolation cut is the main background reducer:

e+%10

E

E-E

cand

candcone

~MW /2

Relative isolation cut: removes >10 in background dominated region (10-20 GeV); signal region (30-50 GeV) is relatively untouched: W signal: Jacobian

peak at ~MW /2


32

W± in PHENIX Central

7/11/2013

e-

e+

• Background estimation:Fit region 10 to 69 GeV/c with a power lawFit region 20 to 50 GeV/c with a power law + Jacobian peak (simulation)

• After cuts, 25% background in signal region for W+ 42% background in signal region for W-

• 30-50 GeV/c – Signal Region • 10-20 GeV/c – Background Dominated


33

Forward rapidity W ±

Measurements

7/11/2013

PHENIX Forward Upgrade Program

B

RPC3

WppFully upgraded in 2012: new upgrades provide trigger rejection to reject low-p muons

1.2 < η < 2.4 (North) -2.2 < η <-1.2 (South)

• High‐pT trigger including RPC: small bending in magnetic field + timing (BBC/RPC)

• Trigger on straight-line tracks through the whole muon arm

• Muon Tracker (MuTr): tracking, triggering• Muon Identifier (MuID): particle ID, triggering• Resistive Plate Chamber (RPC): particle ID, triggering

• Forward Vertex Detector (FVTX)


34

Run 2012 W± AL

7/11/2013

• Boxes are systematic uncertainties from background

• Run 2012 Beam Polarization uncertainty P/P = 3.4% (not shown)

• With the upcoming analysis of the recent high statistics run will we be able to reduce the current uncertainties on Δq.

Beam combined asymmetries for forward and the mid-rapidity results


357/11/2013

Lum

inos

ity p

b-1

2011: BBC<30cm2012: BBC<30cm

2013: BBC<30cm

Run 2013 and Expectation of PHENIX W ProgramYear s (GeV) ∫Ldt (pb-1) Pol. (%) LP2 (pb-1)

2009 500 8.6 39 1.3

2011 500 16 48 3.7

2012 510 30 55 9.1

2013 510 ~156 ~54 45.5

Including Run 2013 data (~63% of luminosity goal), total luminosity ~200 pb-1 in the 30 cm vertex.

• Analyzing fast production data.• Run 2013 production has already begun.


367/11/2013

FVTX

FVTX

VTXFVTX-VTX Track

MuTr Matching

Expected S/B Improvement using FVTX

FVTX covers 1.2 < |η| < 2.4, 2π in φ

FVTX is expected to improve analysis power by:• Precise vertex determination• Better Tracking: FVTX – MuTr track matching (can suppress decay-in-flight background).

First evaluation using two observables above: S/B improved by factor 2

Expected better improvement when implementing the new multi-vertex finder and isolation cone cut!

Muon Arms + FVTX W Detection

FVTX was operational in Run 2012 Much better performance (95% alive) in Run 2013


37

Transverse Physics• A good example of an emergent phenomena in physics

is transverse asymmetries in high energy scattering.• Linked to:

o Orbital Angular Momentumo Gauge link

7/11/2013

Sivers mechanism: Correlation between nucleon spin and parton kT

Phys Rev D41 (1990) 83; 43 (1991) 261

Collins mechanism: Transversity (quark polarization) * Spin-dependence in the jet fragmentation

Nucl Phys B396 (1993) 161


38

Recent PHENIX Transverse Spin Runs

7/11/2013

Year Ös [GeV] Recorded L Pol [%] FOM (P2L)

2006 (Run 6) 200 2.7 pb-1 50 700 nb-1

2008 (Run 8) 200 5.2 pb-1 45 1100 nb-1

2012 (Run12) 200 9.2 pb-1 60 3300 nb-1


39

Forward Neutron AN

7/11/2013

neutron

neutronBBC hits

Single pion exchange?

arXiv:1209.3283


40

Forward Neutron AN

7/11/2013

Forward asymmetryAN = 0.0610.010(stat)0.004(syst)

Backward asymmetryAN = 0.0060.011(stat)0.004(syst)

Forward asymmetryAN = 0.0750.004(stat)0.004(syst)

Backward asymmetryAN = 0.0080.005(stat)0.004(syst)

neutron

chargedparticles

neutron

Interaction trigger with charged particles in beam-beam counter (ZDCBBC trigger)


41

Mid-rapidity 0 and η

• So far, all mid-rapidity transverse asymmetries are consistent with zero.

• {x, Q2} dependence under investigation.

7/11/2013


42

MPC: Forward-rapidity 0 and η

7/11/2013

θπ, η

γ1

γ2

3.1 < |η| < 3.9


43

MPC: 0 and η AN, s=62.4, 200 GeV

• Within uncertainties, and given some differences in kinematics, PHENIX data are in agreement with STAR and E704 measurements.

7/11/2013

p+pη0+X at s=200 GeV/c2


44

Access Higher pT: EM Clusters

7/11/2013

...)(00

fAfAfAclusterA NNNN

STAR pi0 data from:PRL 101 (2008)

STAR 2γ methodPHENIX inclusive cluster preliminary

PHENIX PreliminaryEM clusters

AN vs pT, s=200 GeV


45

J/ψ AN

7/11/2013

AN ≠ 0Color singlet

AN =0Color Octet

• A new test of QCD factorization and role of spin in particle production

• Expect much improved measurements from future high stat runs @RHIC.

• FVTX detector significantly improves resolution and reduces background.

Run 06+08+12


46

kT Asymmetry• The PHENIX central arms provide a good o trigger. Using those large data sets, we can measure

azimuthal angular distribution w.r.t. the azimuth of associated (charged) particle. The strong same and away side peaks in p-p collisions indicate di-jet origin from hard scattering partons.

7/11/2013o- h± azimuthal correlation

Tt

Ttt p

pz

ˆ

Phys. Rev. D 74, 072002 (2006)

http://link.aps.org/abstract/PRD/v74/e072002


47

kT Asymmetry

7/11/2013

• We became interested in a paper (Meng Ta-Chung et al. Phys. Rev. D 1989) describing a method to investigate orbital angular momentum in longitudinally polarized proton-antiproton collisions leading to Drell-Yan pairs.

• Possibility to probe the Wigner functions (correlations between position and transverse momentum)!

• With our di-hadron jet techniques, we applied this to determine if there are any effects in polarized proton-proton collisions.

Like Helicity

Un-like Helicity

kTRkPR

kTR

kPR


48

kT Asymmetry

• Interpretation:o The small asymmetry in jT verifies our

assumption that the third term is suppressed.o The second term may be constrained from

current knowledge of the π0 ALL.

o The first term can be related in the “Meng conjecture” to partonic transverse momentum:

where cij give the initial state weights and Wij give the impact parameter weighting.

7/11/2013

2

2

2

0

0

1

T initial

T hard

T frag

k

k

kQ

2 ij ij i j i jT T T T Tinitial

i j

k c W k k k k


49

Future Forward Di-muon Drell-Yan AN Study

7/11/2013

• Drell-Yan AN accesses quark Sivers effect (f1T

⊥) in proton

• f1T⊥ expected to reverse in sign

from SIDIS to DY.

RHIC 1-year running projection

Semi-inclusive DIS (SIDIS) Drell-Yan

DOE milestone HP13

~2016

fundamentally important test of QCD factorization and gauge-link


50

Future s/ePHENIX

7/11/2013


51

Spin Physics with Forward s/ePHENIX

7/11/2013

Aerogel&

RICH

GEMStation4

EMCal

HCal

GEMStation2

z (cm)

R (cm)

HCal

η~1

η~4

η~-1

R (cm)

GEMStation3

SiliconStation1

MuID

p p p A3He p

Forward field shaper (later slides)

Central silicon tracking

EMCal& Preshower

Optimized for jets, photons and DY over a large range in rapidity (1<eta<4)• Extension of sPHENIX central solenoid• GEM based tracking• Diamond pixel for heavy flavor tagging• RICH based PID (p/K/p)• EM and hadronic calorimetry• Muon identification


52

Summary• PHENIX (and others at RHIC) have already made a

significant contribution to the understanding of the spin composition of the proton.

• Current 500 GeV, high statistics data in-hand with improved detectors will continue that process for the next few years.

• Future detector upgrades (s/ePHENIX) will give us the tools we need to continue through the next decades.

7/11/2013


53

Acknowledgements• Fortunately, this talk follows the RHIC-AGS User’s

Meeting where several of my colleagues gave talks on the Spin Physics program at PHENIX. I have unabashedly stolen many of their slides for this talk.o Scott Wolin, University of Illinois at Urbana-Champaign, (ΔG program)o Mikhail Stepanov, University of Massachusetts, Amherst (W program)o Ming Liu, Los Alamos National Lab, (Transverse program)

• The PHENIX collaboration as a whole.• RHIC Spin Collaboration.• RIKEN/BNL Research Center (RBRC).

7/11/2013


54

Backup

7/11/2013


55

ALLe and ALL

π0π0 Mid-rapidity

7/11/2013

arXiv:1209.3278 [hep-ex]

Particle measured Di-π0 electron

Pseduo-rapidity η<|0.35| η<|0.35|

gluon x sensitivity 0.05<x<0.2 0.05<x<0.2

Advantage Constrains kinematics

Clean channel (from FF), good bg rej. (HBD)

Hurdle Statistics Statistics, sensitive to |ΔG| only

http://arxiv.org/abs/1209.3278


567/11/2013

Abilene Christian University, Abilene, TX 79699, U.S.Department of Physics, Augustana College, Sioux Falls, SD 57197Baruch College, CUNY, New York City, NY 10010-5518, U.S.Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.Physics Department, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.University of California - Riverside, Riverside, CA 92521, U.S.University of Colorado, Boulder, CO 80309, U.S.Columbia University, New York, NY 10027 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 01003-9337, U.S. Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040Morgan State University, Baltimore, MD 21251, U.S.Muhlenberg College, Allentown, PA 18104-5586, 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 11973-5000, U.S.Chemistry Department, Stony Brook University,SUNY, Stony Brook, NY 11794-3400, 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 CEP05315-970, BrazilChina Institute of Atomic Energy (CIAE), Beijing, People's Republic of ChinaPeking University, Beijing, People's Republic of ChinaCharles University, Ovocnytrh 5, Praha 1, 116 36, Prague, Czech RepublicCzech Technical University, Zikova 4, 166 36 Prague 6, Czech RepublicInstitute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8, Czech RepublicHelsinki Institute of Physics and University of Jyväskylä, P.O.Box 35, FI-40014 Jyväskylä, FinlandDapnia, CEA Saclay, F-91191, Gif-sur-Yvette, FranceLaboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F-91128, Palaiseau, FranceLaboratoire de Physique Corpusculaire (LPC), Université Blaise Pascal, CNRS-IN2P3, Clermont-Fd, 63177 Aubiere Cedex, FranceIPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406, Orsay, FranceDebrecen University, H-4010 Debrecen, Egyetem tér 1, HungaryELTE, Eötvös Loránd University, H - 1117 Budapest, Pázmány P. s. 1/A, HungaryKFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences (MTA KFKI RMKI), H-1525 Budapest 114, POBox 49, Budapest, HungaryDepartment of Physics, Banaras Hindu University, Varanasi 221005, IndiaBhabha Atomic Research Centre, Bombay 400 085, IndiaWeizmann Institute, Rehovot 76100, IsraelCenter for Nuclear Study, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, JapanHiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, JapanAdvanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata

Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, JapanKEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, JapanKyoto University, Kyoto 606-8502, JapanNagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki 851-0193, JapanRIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-0198, JapanPhysics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501, JapanDepartment of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, JapanInstitute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305, JapanIHEP Protvino, State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, 142281, RussiaINR_RAS, Institute for Nuclear Research of the Russian Academy of Sciences, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, RussiaJoint Institute for Nuclear Research, 141980 Dubna, Moscow Region, RussiaRussian Research Center "Kurchatov Institute", Moscow, RussiaPNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region, 188300, RussiaSaint Petersburg State Polytechnic University, St. Petersburg, RussiaSkobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Vorob'evy Gory, Moscow 119992, Russia Chonbuk National University, Jeonju, South KoreaEwha Womans University, Seoul 120-750, South KoreaHanyang University, Seoul 133-792, South KoreaKorea University, Seoul, 136-701, South KoreaAccelerator and Medical Instrumentation Engineering Lab, SungKyunKwan University, 53 Myeongnyun-dong, 3-ga, Jongno-gu, Seoul, South KoreaMyongji University, Yongin, Kyonggido 449-728, KoreaDepartment of Physocs and Astronomy, Seoul National University, Seoul, South KoreaYonsei University, IPAP, Seoul 120-749, South KoreaDepartment of Physics, Lund University, Box 118, SE-221 00 Lund, Sweden


58

W± in PHENIX

7/11/2013

Forward (Muon) arm spectrometers:• 1.2 < η < 2.4 (North) -2.2 < η <-1.2 (South), = 2• Muon Tracker (MuTr): tracking, triggering• Muon Identifier (MuID): particle ID, triggering• Resistive Plate Chamber (RPC): particle ID, triggering

Central arm spectrometers:• 2 arms: |η|<0.35, each = /2• Electromagnetic Calorimeter (EMCal: PbSc, PbGl) with fine segmentation ΔφxΔη~0.01x0.01: triggering• Drift Chamber (DC) and Pad Chamber (PC): tracking charged tracks and charge separation• VTX detector (commissioned in 2011)

eWpp

Wpp

e

B

B


59

S/B Ratio in Forward Arm

7/11/2013

• 16 < pT < 60 GeV/c, f > 0.92

S/B ratios:

S/B ratio used for the dilution factor

Factor [x0.5 – x2.0] range, as a conservative uncertainty of the S/B

1D projections of the 2D unbinned maximum likelihood fit onto dw23 (top) and rapidity η (bottom)


60

Preliminary Results

7/11/2013


61

A New Challenge: AN Sign Mismatch?

7/11/2013

• Twist-3 (RHIC) v.s. Sivers (SIDIS)

A possible solution? Kang, Prokudin PRD (2012)Kang, Qiu, Vogelsang, Yuan PRD 2011

SIDIS Data

unknown

Collins dominates?

Need more data!- x-coverage important!


62

Forward AN Challenge: pT Dependence

7/11/2013

- No sign of 1/pT falloff yet.- Collins?- Twist-3 pT-dep not trivial

- Much improved with MPC-EX (2015+)

Sub-process fractions p+p 200GeV

0

x1

Y. Koike, 2012

Valence Quarks’ Sivers or Collins effects?


63

PHENIX Very Forward Detectors

7/11/2013

A combined charged particle tracker and EM pre-shower detector – dual gain readout allows sensitivity to MIPs and full energy EM showers.

•p0 rejection direct photons•p0 reconstruction out to >80GeV


64

Coming soon: MPC-EX (2015+)

7/11/2013

MPC-EX

A combined charged particle tracker and EM pre-shower detector – dual gain readout allows sensitivity to MIPs and full energy EM showers.

•p0 rejection direct photons•p0 reconstruction out to >80GeV

3.1<| |h <3.9

Dir. Photon AN


65

Status of pdfs circa 2004

7/11/2013


66

Status of pdfs circa 2009

)ΔΔΔΔΔ(ΔΔ sdusdudx

Sea anti-quark polarization not well constrained in polarized SIDIS

1 1ΔΣ Δ

2 2p q GS G L L

Quark polarization well measured in DIS: ~30%

7/11/2013

DSSV Global Analysis:Phys. Rev. D 80, 034030 (2009)

Documents

Spin Physics at PHENIX Douglas Fields University of New Mexico For the PHENIX Collaboration