Selected results and future prospects of the high-energy polarized p+p program at RHIC at BNL

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1 1 Selected results and future prospects of the high-energy polarized p+p program at RHIC at BNL

2 Outline 2 Selected results and future prospects Gluon related studies Quark / Anti-quark related studies Experimental aspects: RHIC / PHENIX / STAR Theoretical foundation p p Summary and Outlook

3 Spinning Theoretical Glue: QCD foundation and Spin 3 How do we probe the structure and dynamics of matter in ep vs. pp scattering? e p x Q 2 e d ep F 2 = X q xe 2 qf q (x) Universality p p x 1 x 2 Jet 1 Jet 2 d pp f 1 f 2 h D h f Factorization W 2 Q 2 /x f(x) = f(x) = Momentum contribution + f + (x) + f (x) f + (x) f (x) contribution Spin

4 Spinning Theoretical Glue: QCD foundation and Spin 3 How do we probe the structure and dynamics of matter in ep vs. pp scattering? e p x Q 2 e d ep F 2 = X q xe 2 qf q (x) Universality p p x 1 x 2 W e e d pp f 1 f 2 h D h f Factorization W 2 Q 2 /x f(x) = f(x) = Momentum contribution + f + (x) + f (x) f + (x) f (x) contribution Spin

5 Theoretical foundation 4 Explore proton spin structure using high-energy polarized p+p collisions: Helicity Observable: Quark/Anti-quark polarization (W production) Longitudinal single-spin asymmetry A L f 1 (x 1 ) ˆ(LO, NLO, NNLO) D h f A L = Parity (Spatial inversion) violating for W production! f 2 (x 2 ) X Observable: Gluon polarization (Jet/Hadron production) Double longitudinal single-spin long-range short-range long-range f 1 a LL = f 2 h h Input asymmetry A LL A LL = = f 1 f 2 h a LL D h f f 1 f 2 h D h f

6 Theoretical foundation 4 Explore proton spin structure using high-energy polarized p+p collisions: Helicity Observable: Quark/Anti-quark polarization (W production) Longitudinal single-spin asymmetry A L f 1 (x 1 ) ˆ(LO, NLO, NNLO) D h f A L = Parity (Spatial inversion) violating for W production! f 2 (x 2 ) X Observable: Gluon polarization (Jet/Hadron production) Double longitudinal single-spin long-range short-range long-range f 1 a LL = f 2 h h Input asymmetry A LL A LL = = f 1 f 2 h a LL D h f f 1 f 2 h D h f

7 Theoretical foundation 4 Explore proton spin structure using high-energy polarized p+p collisions: Helicity Observable: Quark/Anti-quark polarization (W production) Longitudinal single-spin asymmetry A L f 1 (x 1 ) ˆ(LO, NLO, NNLO) D h f A L = Parity (Spatial inversion) violating for W production! f 2 (x 2 ) X Observable: Gluon polarization (Jet/Hadron production) Double longitudinal single-spin long-range short-range long-range f 1 a LL = f 2 h h Input asymmetry A LL A LL = = f 1 f 2 h a LL D h f f 1 f 2 h D h f

8 Theoretical foundation 4 Explore proton spin structure using high-energy polarized p+p collisions: Helicity Observable: Quark/Anti-quark polarization (W production) Longitudinal single-spin asymmetry A L f 1 (x 1 ) ˆ(LO, NLO, NNLO) D h f A L = Parity (Spatial inversion) violating for W production! f 2 (x 2 ) X Observable: Gluon polarization (Jet/Hadron production) Double longitudinal single-spin long-range short-range long-range f 1 a LL = f 2 h h Input asymmetry A LL A LL = = f 1 f 2 h a LL D h f f 1 f 2 h D h f

9 Experimental aspects - RHIC 5 The world s first polarized proton-proton collider Siberian Snakes RHIC pc Polarimeter Absolute Polarimeter (H jet) PHENIX STAR Siberian Snakes Spin Rotators Partial Snake Pol. Proton Source 200 MeV Polarimeter Helical Partial Siberian Snake AGS polarimeters Rf Dipole Strong AGS snake

10 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

11 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

12 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

13 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

14 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

15 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

16 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

17 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

18 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=200gev (long. polarization) in 2005, 2006, 2009 and 2015: Jet and Hadron production (Gluon polarization) Production runs at s=500gev (long. polarization) in 2009, 2011, 2012 and 2013: W production (Quark polarization) / Jet and Hadron production (Gluon polarization)

19 Experimental aspects - PHENIX 7 Overview π 0, η, γ Electromagnetic Calorimeter (PbSc/PbGl) ( η <0.35, φ= 2 x π/2) π ±, e, J/ψ e + e - Drift Chamber (DC) Ring Imaging Cherenkov Detector (RICH) Electromagnetic Calorimeter (PbSc/PbGl) µ, J/ψ µ + µ - π 0, η Muon Id/Muon Tracker (1.2< η < π) MPC (3.1< η < π) Relative Luminosity Beam Beam Counter (BBC) (3.0< η<3.9) Zero Degree Calorimeter (ZDC) = ln tan TOF-W RPC3 ZDC South PbSc MuID PbSc PbSc PbSc West South Muon Magnet 10.9 m = 36 ft RICH Aerogel MuTr South PHENIX Detector BB PC3 PC1 PC2 DC MPC Central Magnet BBC (F)VTX Beam View Central Magnet MPC BBC (F)VTX RPC1 Side View PC3 TEC DC PC m = 60 ft RICH PbSc East North TOF-E PbSc North Muon Magnet PbGl PbGl 7.9 m = 26 ft MuID RPC3 ZDC North

20 Experimental aspects - STAR 8 Overview η=-1 η=0 η=+1.0 Calorimetry system with 2π coverage: BEMC EAST WEST η=+1.09 (-1<η<1) and EEMC (1.09<η<2) BEMC EEMC TPC: Tracking and particle TPC EEMC η=+2.0 ID (-1.3<η<1.3) FGT: Tracking (1<η<2) FGT ZDC: Relative luminosity and local polarimetry (500GeV) BBC: Relative luminosity and Minimum bias trigger = ln tan 2

21 Results / Status - Gluon related studies 9 RHIC Gluon studies: Jet-type measurements Jet π + π 0 g parton particle detector σ ij /σ tot Δg Δq Inclusive Jet production (200GeV: Solid line / 500GeV: Dashed line) -1<η<1 gg qg qq q X T x T = 2p T p s (x value at η = 0)

22 Results / Status - Gluon related studies 9 RHIC Gluon studies: Jet-type measurements Jet π + π 0 g parton particle detector σ ij /σ tot Δg Δq Inclusive Jet production (200GeV: Solid line / 500GeV: Dashed line) -1<η<1 gg qg qq q X T x T = 2p T p s (x value at η = 0)

1 / Challenging to provide additional constraint from LHC experiments RHIC mid-rapidity jet production probes x-range around x=0.

23 Results / Status - Gluon related studies 10 Uncertainty of unpolarized gluon distribution function g(x) Large uncertainties of unpolarized gluon distribution function for x > 0.1 / Challenging to provide additional constraint from LHC experiments RHIC mid-rapidity jet production probes x-range around x=0.1 of approximately 0.05 < x < 0.3 New STAR Inclusive Jet cross-section measurement using anti-kt algorithm with improved statistical precision and reduced systematic uncertainties will provide important and needed constraint on g(x) at high x

24 Results 11 Mid-rapidity Inclusive Jet cross-section measurement (1) Unfolded inclusive jet cross-section using anti-k T algorithm (R=0.6) (Smaller dependence on underlying event (UE) and Pile-up) D ij =min 1 k 2 T,i, 1 k 2 T,j! R 2 ij R R 2 ij =( i j ) 2 +( i j ) 2 D i = 1 k 2 T,i d =min({d ij,d i }) If d = D ij : Combine jet i and jet j If d = D i : Define jet i as final jet corrected to particle level for three different pseudo-rapidity regions of η <1, η <0.5 and 0.5< η <1.0 Hadronization and UE corrections evaluated using PYTHIA applied to NLO calculations applied to pure NLO calculations for data comparison Comparison to NLO calculations for CT10, NNPDF3.0 and MRST-W2008 with a preference for CT10

25 Results / Status - Gluon related studies 12 STAR: Mid-rapidity Inclusive Jet cross-section measurement (Run 9) (2) Quantitative comparison between data and theory of (Data-Theory)/ Theory showing UE/hadronization corrections applied to pure NLO calculations Data systematic errors CT10 scale uncertainties CT10 pdf uncertainites

26 Results / Status - Gluon related studies 13 STAR: Mid-rapidity Inclusive Jet cross-section measurement (Run 9) (3) Quantitative comparison between data and theory of (Data-Theory)/ Theory showing UE/hadronization corrections applied to pure NLO calculations Data systematic errors CT10 scale uncertainties CT10 pdf uncertainites

27 Results / Status - Gluon related studies 14 STAR: Mid-rapidity Inclusive Jet A LL measurement (Run 9) at 200GeV L. Adamczyk et al. (STAR Collaboration), arxiv: Run 9 A LL measurement between BB10 and DSSV / Clearly above zero at low p T Larger asymmetry at low p T suggests larger gluon polarization compared to DSSV With global analysis, A LL jet result provides evidence for positive gluon polarization for x > 0.05

28 Results / Status - Gluon related studies 15 STAR: Mid-rapidity Inclusive Jet A LL measurement (Run 12) at 510GeV Run 12 A LL measurement of inclusive jets (anti-k T algorithm) probes smaller x values Run 12 A LL measurement in good agreement with most recent DSSV14 fit including Run 9 A LL results

29 Results / Status - Gluon related studies 16 STAR: Mid-rapidity Inclusive Jet A LL measurement (Run 9) Run 12 A LL measurement (510GeV) and Run 9 of A LL measurement (200GeV) in good agreement in region of overlap vs. x T Large Run GeV data sample will further constrain Δg(x) at low x

30 Results / Status - Gluon related studies 17 PHENIX: Mid-rapidity neutral pion A LL measurement 0 p (GeV/c) T PHENIX Prelim., Run PHENIX shift uncertainty 0 DSSV++ for STAR Prelim. jet, Run 2009 STAR shift uncertainty DSSV++ for jet A LL PHENIX / STAR scale uncertainty 6.7% / 8.8% from pol. not shown A. Adare et al. (PHENIX Collaboration), Phys. Rev. D90 (2014) Data are well described by NLO pqcd calculations New PHENIX Run 13 results at 510GeV Jet p T (GeV/c) Consistency between PHENIX and STAR results!

31 Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) D. deflorian et al., Phys. Rev. Lett. 113 (2014) Wide spread at low x (x<0.05) of alternative fits consistent within 90% of C.L. DSSV: Original global analysis incl. first RHIC results (Run 5/6) DSSV*: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates DSSV - NEW FIT: Strong impact on Δg(x) with RHIC run 9 results: Similar conclusion by independent global analysis of NNPDF: % C.L. for 0.05 <x for 0.05 <x<0.5 E. R. Nocera et al., Nucl. Phys. B887 (2014) 276. better small-x probes are badly needed.

32 Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) D. deflorian et al., Phys. Rev. Lett. 113 (2014) Wide spread at low x (x<0.05) of alternative fits consistent within 90% of C.L. DSSV: Original global analysis incl. first RHIC results (Run 5/6) DSSV*: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates DSSV - NEW FIT: Strong impact on Δg(x) with RHIC run 9 results: Similar conclusion by independent global analysis of NNPDF: % C.L. for 0.05 <x for 0.05 <x<0.5 E. R. Nocera et al., Nucl. Phys. B887 (2014) 276. better small-x probes are badly needed.

33 Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) D. deflorian et al., Phys. Rev. Lett. 113 (2014) Wide spread at low x (x<0.05) of alternative fits consistent within 90% of C.L. DSSV: Original global analysis incl. first RHIC results (Run 5/6) DSSV*: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates DSSV - NEW FIT: Strong impact on Δg(x) with RHIC run 9 results: Similar conclusion by independent global analysis of NNPDF: % C.L. for 0.05 <x for 0.05 <x<0.5 E. R. Nocera et al., Nucl. Phys. B887 (2014) 276. better small-x probes are badly needed.

34 Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) D. deflorian et al., Phys. Rev. Lett. 113 (2014) Wide spread at low x (x<0.05) of alternative fits consistent within 90% of C.L. DSSV: Original global analysis incl. first RHIC results (Run 5/6) DSSV*: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates DSSV - NEW FIT: Strong impact on Δg(x) with RHIC run 9 results: Similar conclusion by independent global analysis of NNPDF: % C.L. for 0.05 <x for 0.05 <x<0.5 E. R. Nocera et al., Nucl. Phys. B887 (2014) 276. better small-x probes are badly needed.

Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) 012001. D. deflorian et al., Phys. Rev. Lett. 113 (2014) 012001. Wide spread at low x (x<0.

35 Results / Status - Gluon polarization program 18 Impact on Δg from RHIC data D. deflorian et al., Phys. Rev. Lett. 113 (2014) D. deflorian et al., Phys. Rev. Lett. 113 (2014) Wide spread at low x (x<0.05) of alternative fits consistent within 90% of C.L. DSSV: Original global analysis incl. first RHIC results (Run 5/6) DSSV*: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates DSSV - NEW FIT: Strong impact on Δg(x) with RHIC run 9 results: Similar conclusion by independent global analysis of NNPDF: % C.L. for 0.05 <x for 0.05 <x<0.5 E. R. Nocera et al., Nucl. Phys. B887 (2014) 276. better small-x probes are badly needed.

36 Results / Status - Gluon related studies 19 Impact on Δg from RHIC data Important constraint from 500GeV and forward rapidity measurements

37 Results / Status - Gluon related studies 20 RHIC Gluon polarization - Correlation Measurements Correlation measurements provide access to LO partonic kinematics through Di-Jet/Hadron production and Photon-Jet production: x 1 (2) = 1 s p T 3 e 3 ( 3) + p T4 e 4 ( 4) Bjorken x-coverage: Current STAR acceptance Released STAR results 3 η x 2 vs. (η,η ) M 3 4 inv = 20 GeV s=500 GeV η x 2 p p gg, qg, qq x 1 x 2 Di-Jet production = ln x 1 x 2 M = p s p x 1 x 2 p T

38 Results / Status - Gluon related studies 21 Mid-rapidity STAR Di-Jet cross-section (Run 9) and A LL measurement (Run 9) Data are well Full Acceptance STAR Preliminary Run 9 described by NLO pqcd plus hadronization and underlying event corrections A LL STAR Preliminary Run 9 A LL measurements fall in-between M [GeV/c ] GRSV-STD and DSSV p s = 200 GeV M = p s p x 1 x = ln x 1 x 2

For new forward calorimeter system FCS, assume hadronic calorimetry with 0.9 All jet calculations at NLO (Code: D. deflorian and W.

39 Future prospects - Gluon polarization program 22 Possible forward detector layout (FCS / FTS: Forward Calor./ Tracking System) Efficiencies for EAST / WEST / EEMC all defined using STAR jet efficiencies. For new forward calorimeter system FCS, assume hadronic calorimetry with 0.9 All jet calculations at NLO (Code: D. deflorian and W. Vogelsang) / simulations with di-jet E T cuts of 5GeV/8GeV (Cone algo.) Systematics: Relative luminosity use δr = (Run 9 Inclusive Jet value) P/L numbers : P = 60% and L delivered = 1000pb -1 with 2/3 for L recorded / L delivered (~ 1 long RHIC run!)

40 Future prospects - Gluon polarization program 23 dσ/dx 1 (dσ/dx 2 ) (pb) dσ/dx 1 (dσ/dx 2 ) (pb) Kinematic coverage - Simulations / Central < η 3 (4) < 0 / -0.8 < η 4 (3) < 0 (EAST / EAST) x 1 x Cone alg. (R=0.7) / E T3 > 5GeV x 1 (xe 2 ) T4 > 8GeV < η 3 (4) < 0 / 1.2 < η 4 (3) < (EAST / EEMC) x 1 x x 1 (x 2 ) dσ/dx 1 (dσ/dx 2 ) (pb) dσ/dx 1 (dσ/dx 2 ) (pb) 10 x 1 x Cone alg. (R=0.7) / E T3 > 5GeV x 1 (xe 2 ) T4 > 8GeV < η 3 (4) < 0.8 / 1.2 < η 4 (3) < (WEST / EEMC) T3-0.8 < η 3 (4) < 0 / 0 < η 4 (3) < +0.8 (EAST / WEST) x 1 x x 1 (x 2 ) T4 dσ/dx 1 (dσ/dx 2 ) (pb) dσ/dx 1 (dσ/dx 2 ) (pb) Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV < η 3 (4) < 0.8 / 0 < η 4 (3) < (WEST / WEST) 10 5 x x Cone alg. (R=0.7) / E T3 > 5GeV x 1 (xe 2 ) T4 > 8GeV < η 3 (4) < 1.8 / 1.2 < η 4 (3) < (EEMC / EEMC) x 1 x x 1 (x 2 )

41 δr = A LL A LL Future prospects - Gluon polarization program A LL projections / Central GRSV STD DSSV (EAST / EAST) M (GeV) A LL Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV GRSV STD DSSV (EAST / WEST) 0 Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV 0 Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV 0 Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8G Delivered Luminosity = 1000pb Delivered Luminosity = 1000pb -1 Delivered Luminosity = 1000pb -1 x Polarization = 60% Polarization = 60% Polarization = 60% M (GeV) M (GeV) M (GeV) GRSV STD GRSV STD GRSV STD 0.3 DSSV DSSV DSSV 0.25 (EAST / EEMC) (WEST / EEMC) (EEMC / EEMC) A LL M (GeV) A LL A LL Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8G Delivered Luminosity = 1000pb -1 Polarization = 60% GRSV STD DSSV (WEST / WEST) M (GeV) 24

42 Future prospects - Gluon polarization program 25 Kinematic coverage - Simulations / Forward dσ/dx 1 (dσ/dx 2 ) (pb) dσ/dx 1 (dσ/dx 2 ) (pb) Cone alg. (R=0.7) / E T3 > 5GeV x 1 (xe 2 ) T4 > 8GeV x 1 (x 2 ) x 1 x 2 T3-0.8 < η 3 (4) < 0 / 2.8 < η 4 (3) < 3.7 (EAST / FCS) 1.2 < η 3 (4) < 1.8 / 2.8 < η 4 (3) < 3.7 (EEMC / FCS) x 1 x T4 dσ/dx 1 (dσ/dx 2 ) (pb) dσ/dx 1 (dσ/dx 2 ) (pb) Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV < η (4) < 0.8 / 2.8 < η 4 (3) < (WEST / FCS) 10 5 x x Cone alg. (R=0.7) / E x 1 (x 2 ) T3 > 5GeV E T4 > 8GeV < η (4) < 3.7 / 2.8 < η 4 (3) < (FCS / FCS) 10 5 x x x 1 (x 2 )

43 Future prospects - Gluon polarization program Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV Cone alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV x 10-2 Delivered Luminosity = 1000pb -1 x 10-2 Delivered Luminosity = 1000pb -1 Polarization = 60% Polarization = 60% x 10-2 (EAST / FCS) Cone alg. (WEST (R=0.7) / FCS) / E T3 > 5GeV E T4 > 8GeV 0.15 x 10-2 Delivered 0.1 Luminosity = 1000pb Polarization = 60% DSSV 0-0 GRSV STD CTEQ6M DSSV GRSV STD MRST A LL projections / Forward A LL -0.1 GRSV STD Cone alg. DSSV (R=0.7) / E T3 > 5GeV E T4 > 8GeV x 10-2 Delivered Luminosity = 1000pb -1 δr = Polarization = 60% M (GeV) 0.2 (EEMC / FCS) 0.15 x A LL GRSV STD DSSV M (GeV) A LL A LL A LL 0.15 x GRSV STD < η 3 (4) < 0 / 1.2 < η 4 (3) < 1.8 DSSV (EAST Cone / EEMC) alg. (R=0.7) / E T3 > 5GeV E T4 > 8GeV x 10-2 Delivered Luminosity = 1000pb -1 Polarization = 60% M (GeV) (FCS / FCS) GRSV STD DSSV M (GeV) M (GeV) E T3 > 5GeV E T4 > 8GeV Cone alg. (R=0.7) / 26

44 Results / Status - q / qbar related studies 27 Probing the quark flavor structure: W boson production (1) p p x 1 W + (W ) x 2 e ( e) e + (e ) y l = y W ln 1 + cos 1 cos y l p T = p T = M W 2 sin x 1 = M W s ey W x 2 = M W s e y W M W s =0.16 Key signature: High p T lepton (e - /e + )(Max. M W /2) - Selection of W + /W - : Charge sign discrimination of high p T lepton Required: Lepton/Hadron discrimination dσ/dp T (pb/gev) W + W - (PDF: CTEQ5M) Total cross-section: 100.9pb Total cross-section: 20.5pb -1 < y e < 1 p T > 0GeV/c p T (GeV) dσ/dp T (pb/gev) W + W - (PDF: CTEQ5M) Total cross-section: 14.3pb Total cross-section: 8.0pb 1 < y e < 2 p T > 0GeV/c p T (GeV) Total ( s=500gev) σ(w + )=135pb and σ(w - )=42pb

45 Results / Status - q / qbar related studies 27 Probing the quark flavor structure: W boson production (1) p p x 1 W + (W ) x 2 e ( e) e + (e ) y l = y W ln 1 + cos 1 cos y l p T = p T = M W 2 sin x 1 = M W s ey W x 2 = M W s e y W M W s =0.16 Key signature: High p T lepton (e - /e + )(Max. M W /2) - Selection of W + /W - : Charge sign discrimination of high p T lepton Required: Lepton/Hadron discrimination dσ/dp T (pb/gev) W + W - (PDF: CTEQ5M) Total cross-section: 83.3pb Total cross-section: 19.3pb -1 < y e < 1 p T > 25GeV/c p T (GeV) dσ/dp T (pb/gev) W + W - (PDF: CTEQ5M) Total cross-section: 5.9pb Total cross-section: 5.0pb 1 < y e < 2 p T > 25GeV/c p T (GeV) Total ( s=500gev) σ(w + )=135pb and σ(w - )=42pb

46 Results / Status - q / qbar related studies 28 Probing the quark flavor structure: W boson production (2) LHC Tevatron RHIC x 2 1 y=-4 y=-3 y=-2 y=-1 y= y=1 e +/- pseudo-rapidity Approximate kinematic range at RHIC: 0.06 < x < 0.4 for -2 < η < x 1 = M W s ey W x 2 = M W s e y W M W s =0.16 y=2 y=3 y=4 Measurement at LHC in high-x range would require very forward measurements x 1

47 Results / Status - q / qbar related studies 29 Probing dbar / ubar ratio ar RHIC: QCD sea p W + (W ) e ( e) p e + (e ) R(x F ) W + W = u(x 1 ) d(x 2 )+ d(x 1 )u(x 2 ) ū(x 1 )d(x 2 )+d(x 1 )ū(x 2 ) STAR coverage at mid-rapidity: 0.1 < x < 0.3 for -1 < η < 1 Constraints on global fitting for dbar/ubar through W production at higher Q 2 compared E906 Independent cross-check of Drell-Yan data

48 Results / Status - q / qbar related studies 30 W cross-section ratio measurements Run 11 + Run 12 preliminary result: ~100pb -1 Run 13 data sample with ~300pb -1 will provide important improvement on precision Planned Run 17 data sample of ~400pb -1

49 Results / Status - q / qbar related studies 31 W cross-section ratio measurements W boson kinematics can be determined by reconstructing the W kinematics via its recoil Combination of data/mc simulations allows W boson rapidity reconstruction Critical for transverse single-spin asymmetry result of W production probing Sivers sign change

50 Results / Status - q / qbar related studies 32 A e L A e+ L [ ū(x (x 1,x 2 ) 1)d(x 2 )(1 cos θ) 2 d(x 1 )ū(x 2 )(1 + cos θ) 2 ] [ū(x (x 1,x 2 ) 1)d(x 2 )(1 cos θ) 2 + d(x 1 )ū(x 2 )(1 + cos θ) 2 ] Probing the quark flavor structure: W boson production (x 1,x 2 ) (x 1,x 2 ) e 1 2 x 1 x 2 x 1 x 2 [ d(x1 )u(x 2 )(1 + cos θ) 2 u(x 1 ) d(x 2 )(1 cos θ) 2] [ d(x1 )u(x 2 )(1 + cos θ) 2 + u(x 1 ) d(x 2 )(1 cos θ) 2] 1 e e + 2 x 1 x 2 x 1 x 2 e A L p s = 500 GeV p +p W ± + X e ± + X STAR s = 500 GeV e 25 < E T < 50 GeV W A W L = ū ū W + A W + L = u u A W L = 1 2 A W + L = 1 2 ū ū d d W W + σ + σ σ + +σ RHICBOS DNS-K DNS-KKP DSSV08 CHE DSSV08 A W + L = d d η e x 1 x 2 x 1 x 2 x 1 x 2 d d u u A L A W L = = d d

51 Recent Results results / Status - Quark - q / qbar Anti-quark related pol. studies program 33 STAR W A L results / projections Measured asymmetries constrain anti-quark polarizations: Larger asymmetry for W - suggest large anti-u quark polarization! Critical: Measurement of W + and W - asymmetries as a function η e Extension of backward / forward η e acceptance enhances sensitivity to anti-u / anti-d quark polarization STAR Forward GEM Tracker (1< η e <2) L. Adamczyk et al. (STAR Collaboration), arxiv:

52 Recent Results results / Status - Quark - q / qbar Anti-quark related pol. studies program 33 STAR W A L results / projections Measured asymmetries constrain anti-quark polarizations: Larger asymmetry for W - suggest large anti-u quark polarization! Critical: Measurement of W + and W - asymmetries as a function η e Extension of backward / forward η e acceptance enhances sensitivity to anti-u / anti-d quark polarization STAR Forward GEM Tracker (1< η e <2)

53 Recent Results results / Status - Quark - q / qbar Anti-quark related pol. studies program 33 STAR W A L results / projections Measured asymmetries constrain anti-quark polarizations: Larger asymmetry for W - suggest large anti-u quark polarization! Critical: Measurement of W + and W - asymmetries as a function η e Extension of backward / forward η e acceptance enhances sensitivity to anti-u / anti-d quark polarization STAR Forward GEM Tracker (1< η e <2)

54 Results / Status - q / qbar related studies 34 PHENIX W A L mid-rapidity results Run 11+12: Mid-rapidity results in good agreement with DSSV14

55 Results / Status - q / qbar related studies 35 PHENIX W A L mid-rapidity and forward rapidity results Compilation of PHENIX Run 13 forward rapidity and mid-rapidity results together with STAR midrapidity results

56 Results / DSSV++ Status - Global q / qbar Analysis related studies 36 Impact of new DSSV global fit result D. de Florian et al., Phys. Rev. Lett. 101 (2008) RHIC Spin Collaboration (2012) From recent DSSV++ result incl. STAR A L data: Z ū(x, Q 2 )dx 0.02 Z d(x, Q 2 )dx 0.05 M W / p s =0.16

57 Summary / Outlook 37 Gluon polarization program Several final states (Hadron / Jet) have been measured all pointing to the same conclusion that the gluon polarization is small consistent with COMPASS findings Precise Run 9 A LL measurement: Non-zero ΔG of similar magnitude as quark polarization! First Di-Jet measurement opens the path to constrain the shape of Δg New inclusive jet cross-section: Important constrain for unpol. gluon at high x W boson program Mid-rapidity: New W - results suggest large anti-u quark polarization along with broken QCD sea Strong physics case of unpolarized dbar/ubar probe using W production Backward/Forward rapidity: Upgrade of PHENIX forward muon detector (Muon Trigger) and STAR FGT (Forward GEM Tracker) Run 13 / 15 and future Run 13: Long. 510GeV Run 13 (~300pb -1 rec.): W (Anti-quarks) and Jet production (Gluons) Run 15: 200GeV (Run 15) with long. / trans. pol. p-p running and for the first time polarized p-a running Future (Run 17 and beyond): Additional long 500GeV prod. runs Drell-Yan (Run 17) and Forward Di-Jets

Future prospects of di-jet production at. forward rapidity constraining Δg(x) at low x in. polarized p+p collisions at RHIC

Future prospects of di-jet production at forward rapidity constraining Δg(x at low x in polarized p+p collisions at RHIC Bernd Surrow QCD Evolution Workshop - QCD! Santa Fe, NM, May, Bernd Surrow Outline