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

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1 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

2 Outline Gluon polarization program Current results / status Future prospects based on forward di-jet production Experimental aspects: RHIC / Theoretical foundation p p Summary and Outlook QCD Evolution Workshop - QCD! Santa Fe, NM, May,

3 Theoretical foundation How do we probe the structure and dynamics of matter in ep vs. pp scattering? e p x Q e d ep F = X q xe qf q (x Universality p p x x Jet Jet d pp f f h D h f Factorization W Q /x f(x = f(x = Momentum contribution + f + (x + f (x f + (x f (x contribution Spin QCD Evolution Workshop - QCD! Santa Fe, NM, May,

Theoretical foundation Explore proton spin structure using high-energy polarized p+p collisions f f h Observable: Gluon polarization (Jet/Hadron production!

4 Theoretical foundation Explore proton spin structure using high-energy polarized p+p collisions f f h Observable: Gluon polarization (Jet/Hadron production! Double longitudinal single-spin long-range short-range long-range f a LL = f h h Input asymmetry = ++ + QCD Evolution Workshop - QCD! Santa Fe, NM, May, = f f h a LL D h f f f h D h f

5 Experimental aspects - RHIC 5 The world s first polarized proton-proton collider Siberian Snakes RHIC pc Polarimeter Absolute Polarimeter (H jet PHENIX Siberian Snakes Spin Rotators Partial Snake Pol. Proton Source MeV Polarimeter Helical Partial Siberian Snake AGS polarimeters Rf Dipole Strong AGS snake QCD Evolution Workshop - QCD! Santa Fe, NM, May,

6 Experimental aspects - RHIC 6 Polarized p-p collisions Production runs at s=gev (long. polarization in 5, 6, 9: Jet and Hadron production (Gluon polarization Production runs at s=5gev (long. polarization in 9,, and : W production (Quark polarization / Jet and Hadron production (Gluon polarization QCD Evolution Workshop - QCD! Santa Fe, NM, May,

9<< BEMC EEMC TPC: Tracking and particle TPC EEMC =+. ID (-.<<. FGT: Tracking (<< FGT ZDC:

7 Experimental aspects - 7 Overview =- = =+. Calorimetry system with π coverage: BEMC EAST WEST =+.9 (-<< and EEMC (.9<< BEMC EEMC TPC: Tracking and particle TPC EEMC =+. ID (-.<<. FGT: Tracking (<< FGT ZDC: Relative luminosity and local polarimetry (5GeV BBC: Relative luminosity and Minimum bias trigger = ln tan QCD Evolution Workshop - QCD! Santa Fe, NM, May,

Results / Status - Gluon polarization program 8 Mid-rapidity Inclusive Jet measurement (Run 9 Preliminary Run 9 Preliminary Run 9 Run 9 measurement between

8 Results / Status - Gluon polarization program 8 Mid-rapidity Inclusive Jet measurement (Run 9 Preliminary Run 9 Preliminary Run 9 Run 9 measurement between GRSV-STD and / Clearly above zero at low p T Larger asymmetry at low p T suggests larger gluon polarization compared to QCD Evolution Workshop - QCD! Santa Fe, NM, May,

9 Results / Status - Gluon polarization program 9 Impact on Δg from RHIC data D. deflorian et al., arxiv:.9 D. deflorian et al., arxiv:.9 Wide spread at low x (x<.5 of alternative fits consistent within 9% of C.L. : Original global analysis incl. first RHIC results (Run 5/6 *: New COMPASS inclusive and semi-inclusive results in addition to Run 5/6 RHIC updates - NEW FIT: Strong impact on Δg(x with RHIC run 9 results Positive for x >.5! better small-x probes are badly needed. QCD Evolution Workshop - QCD! Santa Fe, NM, May, D. deflorian et al., arxiv:.9

10 Results / Status - Gluon polarization program RHIC Gluon polarization - Correlation Measurements Correlation measurements provide access to partonic kinematics through Di-Jet/Hadron production and Photon-Jet production:! x ( = s p T e ( + p T e ( Di-Jet production / Photon-Jet production p p gg, qg, qq x x p T Di-Jet production Di-Jets: All three (LO QCD-type processes contribute: gg, qg and qq Photon-Jet: One dominant underlying (LO process Larger cross-section for di-jet production compared to photon p qg x related measurements x p T Photon reconstruction more challenging than jet reconstruction p Full NLO framework exists Input to Global QCD analysis Photon-Jet production QCD Evolution Workshop - QCD! Santa Fe, NM, May,

11 Results / Status - Gluon polarization program Mid-rapidity Di-Jet cross-section (Run 9 and measurement (Run 9 Data are well Full Acceptance Preliminary Run 9 described by NLO pqcd plus hadronization and underlying event corrections Preliminary Run 9 measurements fall in-between M [GeV/c ] QCD Evolution Workshop - QCD! Santa Fe, NM, May, GRSV-STD and M = p s p x x + = ln x x

12 Results / Status - Gluon polarization program Mid-rapidity Di-Jet measurement in bins of (Run 9 East - East and West - West Barrel East Barrel - West Barrel Full Acceptance.8.6 MC GS-C(pdf set NLO 9 Data Systematic Uncertainties.8.6 Scale uncertainty GRSV std.8.6 Preliminary Run 9.. Preliminary Run Preliminary Run M [GeV/c ] M [GeV/c ] M [GeV/c ] East West East West Run 9 data: First rapidity dependent di-jet measurement Constrain x dependence! =- = = =- = = M = p s p x x + = ln x x QCD Evolution Workshop - QCD! Santa Fe, NM, May,

13 Future prospects - Gluon polarization program Current acceptance Released results Kinematic coverage - (-Vector Kinematics: x x, vs. ( M x, vs. ( M QCD Evolution Workshop - QCD! Santa Fe, NM, May, inv inv = GeV = 6 GeV s=5 GeV s=5 GeV x x + = ln x x M = p s p x x x, vs. ( M x, vs. ( M inv inv = GeV = 8 GeV s=5 GeV s=5 GeV x x

14 Future prospects - Gluon polarization program Current acceptance Released results Kinematic coverage - (-Vector Kinematics: x x x vs. (, M vs. (, M QCD Evolution Workshop - QCD! Santa Fe, NM, May, inv inv = GeV = 6 GeV s=5 GeV s=5 GeV x x + = ln x x M = p s p x x x x vs. (, M vs. (, M inv inv = GeV = 8 GeV s=5 GeV s=5 GeV x x

15 Future prospects - Gluon polarization program 5 Current acceptance Released results Individual Partonic asymmetries QCD Evolution Workshop - QCD! Santa Fe, NM, May, gg all qq all vs. (, vs. (, gg a LL qq a LL qg all vs. (, Jet measurements do not distinguish between gg / qg and qq jets Size and thus weight of partonic asymmetries (Here LO different for different topological configurations qg a LL

16 Future prospects - Gluon polarization program 6 Forward detector concept / Assumptions on projections = =+. =+.9 EAST WEST QCD Evolution Workshop - QCD! Santa Fe, NM, May, EEMC FCS =+. =+.5 =+. Efficiencies for EAST / WEST / EEMC all defined using jet efficiencies. For new forward system FCS, assume hadronic calorimetry with.9!!!!!! Single Jet Efficiency p (GeV/c T All jet calculations at NLO (Code: D. deflorian and W. Vogelsang / simulations with 5GeV/8GeV cuts Systematics: Relative luminosity use δr = 5 - (Run 9 Inclusive Jet value P/L numbers : P = 6% and L delivered = pb - with / for L recorded / L delivered (~ long RHIC run!

17 Future prospects - Gluon polarization program 7 Wide spread at low x (x<.5 of alternative fits consistent within 9% of C.L. Sensitivity range D. deflorian et al., arxiv:.9 x g(x,q Q = GeV.5 GRSV-STD J. Soffer ( x (8 and GRSV-STD have been used for all projections in NOTE: GRSV-STD is much smaller than 9% C.L. envelope for x <.5 AND (8 is smaller in magnitude for x<.5 compared to 9% C.L. envelope Therefore: Uncertainties for x <.5 are larger than by the range of (8 and GRSV-STD! QCD Evolution Workshop - QCD! Santa Fe, NM, May,

18 Future prospects - Gluon polarization program 8 dσ/dx (dσ/dx dσ/dx (dσ/dx Kinematic coverage T - Simulations T / Central < ( < / -.8 < ( < (EAST / EAST x x Cone alg. (R=.7 / E T > 5GeV x (xe T < ( < /. < ( < (EAST / EEMC 5 x x x (x QCD Evolution Workshop - QCD! Santa Fe, NM, May, dσ/dx (dσ/dx dσ/dx (dσ/dx < ( < / < ( < +.8 (EAST / WEST x x dσ/dx (dσ/dx Cone alg. (R=.7 / E T > 5GeV x (xe T 8 < ( <.8 /. < ( < (WEST / EEMC 5 x x x (x dσ/dx (dσ/dx Cone alg. (R=.7 / E T > 5GeV E T 8 < ( <.8 / < ( < (WEST / WEST 5 x x Cone alg. (R=.7 / E T > 5GeV x (xe T 8. < ( <.8 /. < ( < (EEMC / EEMC 5 x x x (x

19 Future prospects - Gluon polarization program 9 dσ/dm (pb/gev Cross-sections / Central Cone alg. (R=.7 / E T > 5GeV E T pb CTEQ6M pb MRST dσ/dm (pb/gev 6 5 T > T > 9977 pb CTEQ6M 8567 pb MRST dσ/dm (pb/gev Cone alg. (R=.7 / 6 5 E T > 5GeV E T 65 pb CTEQ6M pb MRST < ( < / -.8 < ( < (EAST / EAST < ( < / < ( < +.8 (EAST / WEST < ( <.8 / < ( <.8 (WEST / WEST dσ/dm (pb/gev 6 5 T > T > 7789 pb CTEQ6M 77 pb MRST dσ/dm (pb/gev 6 5 T > T > pb CTEQ6M 8975 pb MRST dσ/dm (pb/gev 6 5 T > T > 68 pb CTEQ6M pb MRST < ( < /. < ( <.8 (EAST / EEMC < ( <.8 /. < ( <.8 (WEST / EEMC < ( <.8 /. < ( <.8 (EEMC / EEMC QCD Evolution Workshop - QCD! Santa Fe, NM, May,

20 δr = 5 - QCD Evolution Workshop - QCD! Santa Fe, NM, May, Future prospects - Gluon polarization program projections / Central (EAST / EAST Cone alg. (R=.7 / E T > 5GeV E T (EAST / WEST Cone alg. (R=.7 / E T > 5GeV E T Cone alg. (R=.7 / E T > 5GeV E T Cone alg. (R=.7 / E T > 5GeV E T > 8G Delivered Luminosity = pb - -. Delivered Luminosity = pb - Delivered Luminosity = pb - x Polarization = 6% Polarization = 6% Polarization = 6% (EAST / EEMC.5 (WEST / EEMC.6 (EEMC / EEMC Cone alg. (R=.7 / E T > 5GeV E T > 8G Delivered Luminosity = pb - Polarization = 6% (WEST / WEST

21 Future prospects - Gluon polarization program Kinematic coverage - Simulations / Forward dσ/dx (dσ/dx dσ/dx (dσ/dx QCD Evolution Workshop - QCD! Santa Fe, NM, May, x x T -.8 < ( < /.8 < ( <.7 (EAST / FCS Cone alg. (R=.7 / E T > 5GeV x (xe T. < ( <.8 /.8 < ( <.7 (EEMC / FCS x x x (x T dσ/dx (dσ/dx dσ/dx (dσ/dx Cone alg. (R=.7 / E T > 5GeV E T 8 < 7 ( <.8 /.8 < ( <.7 6 (WEST / FCS 5 x x Cone alg. (R=.7 / E x (x T > 5GeV E T 8.8 < 7 ( <.7 /.8 < ( <.7 6 (FCS / FCS 5 x x x (x

22 Future prospects - Gluon polarization program Cross-sections / Forward dσ/dm (pb/gev dσ/dm (pb/gev T > T > -.8 < ( < /.8 < ( <.7 (EAST / FCS 9 pb CTEQ6M 7 pb MRST T > T > < ( <.8 /.8 < ( <.7 (WEST / FCS 5599 pb CTEQ6M 589 pb MRST dσ/dm (pb/gev dσ/dm (pb/gev Cone alg. (R=.7 / E T > 5GeV E T pb CTEQ6M < ( <.8 /.8 < ( <.7 (EEMC / FCS 857 pb MRST T > T >.8 < ( <.7 /.8 < ( <.7 (FCS / FCS 9898 pb CTEQ6M 788 pb MRST QCD Evolution Workshop - QCD! Santa Fe, NM, May,

23 Cone alg. (R=.7 / E T > 5GeV E T Cone alg. (R=.7 / E T > 5GeV E T x - Delivered Luminosity = pb - x - Delivered Luminosity = pb - Polarization = 6% Polarization = 6%..5 (EAST / FCS Cone alg. (WEST (R=.7 / FCS / E T > 5GeV E T x -.5 x - Delivered. Luminosity = pb -. Polarization = 6%.5.5 CTEQ6M - MRST projections / Forward -. Cone alg. (R=.7 / E -.5 T > 5GeV E T x - Delivered Luminosity = pb - δr = 5 - Polarization = 6%. (EEMC / FCS.5 x QCD Evolution Workshop - QCD! Santa Fe, NM, May, Future prospects - Gluon polarization program x < ( < /. < ( <.8 (EAST Cone / EEMC alg. (R=.7 / E T > 5GeV E T x - Delivered Luminosity = pb - Polarization = 6% (FCS / FCS E T > 5GeV E T Cone alg. (R=.7 /

24 Future prospects - Gluon polarization program PYTHIA simulations incl. detector effects di-jet mass particle level versus detector level di-jet mass particle level versus detector level particle dijet mass (GeV/c particle dijet mass (GeV/c East/FCS West/FCS Entries: 6 Entries: detector dijet mass (GeV/c detector dijet mass (GeV/c particle dijet mass (GeV/c di-jet mass particle level versus detector level EEMC/FCS Entries: 76 particle dijet mass (GeV/c di-jet mass particle level versus detector level FCS/FCS Entries: detector dijet mass (GeV/c detector dijet mass (GeV/c Invariant mass distribution based on PYTHIA simulations incl. detector effects (Only calorimetry! Next: Specify resolution of forward detector system / UE events studies / Jet reconstruction studies QCD Evolution Workshop - QCD! Santa Fe, NM, May,

Summary 5 Status: Gluon polarization program: First Di-Jet measurement opens the path to constrain the shape of Δg Run 9 results: Precise measurement suggesting non-zero ΔG New global analysis by :

Run BUR request: 6 weeks with L delivered = 75pb - and 6% LOI for forward upgrade focusing on forward pp/pa program in preparation!

25 Summary 5 Status: Gluon polarization program: First Di-Jet measurement opens the path to constrain the shape of Δg Run 9 results: Precise measurement suggesting non-zero ΔG New global analysis by : Non-zero Δg(x for x >.5 Larger uncertainties for x <.5, i.e. below current RHIC kinematic region! Run BUR request: 6 weeks with L delivered = 75pb - and 6% LOI for forward upgrade focusing on forward pp/pa program in preparation! Forward jet production: Extend jet measurements at forward rapidity probing Δg(x as low as - in x Challenging measurement with good control of sys. uncertainties important (Assume ~ long RHIC run! Additional probes to be studied: π -jet correlations! Important step prior to a future Electron-Ion Collider (EIC ~5! QCD Evolution Workshop - QCD! Santa Fe, NM, May,

26 dσ/dx (dσ/dx dσ/dx (dσ/dx QCD Evolution Workshop - QCD! Santa Fe, NM, May, Outlook - Run (GeV Kinematic coverage - Simulations / Central < ( < / -.8 < ( < (EAST / EAST x x dσ/dx (dσ/dx Cone alg. (R=.7 / E T > 5GeV x (xe T < ( < /. < ( < (EAST / EEMC 5 x x x (x dσ/dx (dσ/dx < ( < / < ( < +.8 (EAST / WEST x x Cone alg. (R=.7 / E T > 5GeV x (xe T 8 < ( <.8 /. < ( < (WEST / EEMC 5 x x x (x dσ/dx (dσ/dx dσ/dx (dσ/dx Cone alg. (R=.7 / E T > 5GeV E T < ( <.8 / < ( <.8 (WEST / WEST x x Cone alg. (R=.7 / E T > 5GeV x E T (x 8. < ( <.8 /. < ( < (EEMC / EEMC 5 x x x (x

27 δr = 5 - projections / Central (EAST / EAST (EAST / EEMC QCD Evolution Workshop - QCD! Santa Fe, NM, May, Outlook - Run (GeV Cone alg. (R=.7 / E T > 5GeV E T (EAST / WEST Cone alg. (R=.7 / E T > 5GeV E T Delivered 5 5 Luminosity 5 = 575pb Polarization = 6% (WEST / EEMC Cone alg. (R=.7 / E T > 5GeV E T > 8G Delivered Luminosity = 75pb - Polarization = 6% (WEST / WEST Cone alg. (R=.7 / E T > 5GeV E T > 8G Delivered 5 5Luminosity 5 = 575pb Polarization = 6% (EEMC / EEMC

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

1 Selected results and future prospects of the high-energy polarized p+p program at RHIC at BNL Outline 2 Selected results and future prospects Gluon related studies Quark / Anti-quark related studies