1. NLO QCD fits to polarized DIS & SIDIS data NLO QCD fits to polarized DIS & SIDIS data Rodolfo Sassot Universidad de Buenos Aires Global Analysis Workshop, BNL October 8, 2007

2. R. Sassot BNL, October 8, 20072 why spin? indispensable tool for unveiling hadron structure, why polarized DIS? historical benchmark for hadron structure, spin & unexpected physics. 90’s experimental programs. QCD improved description for spin dependent processes LO vs. NLO why NLO QCD global fits?

3. R. Sassot BNL, October 8, 20073 flavor and quark-antiquark discriminatrion, what do we get from data? fits to inclusive/semi-inclusive polarized data. uncertainties in pPDFs: Δq, Δg. how can we improve the present picture? further constraints from forthcoming data. fragmentation functions. ¯ impact “direct” Δg measurements. increasead statistics, new/forthcoming data why polarized SIDIS? sea quarks and flavor dependence in hadronization.

4. R. Sassot BNL, October 8, 20074 The case for pSIDIS: pDIS flavor decomposition

5. R. Sassot BNL, October 8, 20075 The case for pSIDIS: Flavor decomposition in pSIDIS

6. R. Sassot BNL, October 8, 20076 DNS NLO combined analysis: parameterizations pDIS can probe: pSIDIS give access to: positivity relative to MRST02: 20 parameters A.D. Maritn et al. Eur.Phys.J.C28 (2002) 455 D. de Florian, G. Navarro, R.S. Phys.Rev.D71 094018 (2005)

7. R. Sassot BNL, October 8, 20077 DNS NLO combined analysis: data

8. R. Sassot BNL, October 8, 20078 Fragmentation functions input in DNS: KRE: S. Kretzer Phys.Rev.D62 054001 (2000) KKP: B. A. Kniehl, G. Kramer, B. Potter, Nucl.Phys.B582 514 (2000) flavor separation :

9. R. Sassot BNL, October 8, 20079 DNS Results: 478-20=458 d.o.f 313 pDIS 165 pSIDIS

10. R. Sassot BNL, October 8, 200710 Uncertainties: J. Pumplin et al. Phys.Rev.D65 014011 (2002)

11. R. Sassot BNL, October 8, 200711

12. R. Sassot BNL, October 8, 200712 Consistency with independent measurements: G. Navarro, R.S. PRD74 011502 (2006)

13. R. Sassot BNL, October 8, 200713 STAR Coll., PRL97, 252001, (2006)

14. R. Sassot BNL, October 8, 200714 Next steps: DSS FFs: kaon fragmentation, h + /h - MSTW PDFs: positivity constraints, evolution New Compass SIDIS data: flavor at low x Compass/Hermes DIS data (Q2-bin): gluon shape? RHIC data: A LL, jets: Δg

15. R. Sassot BNL, October 8, 200715 New “DSSV” pPDFs: pre-pre-pre-pre-preliminary…. NEW

16. R. Sassot BNL, October 8, 200716 New “DSSV” pPDFs: pre-pre-pre-pre-preliminary from Daniel’s talk why has Δs changed?? old FFs were overestimated

17. R. Sassot BNL, October 8, 200717

18. R. Sassot BNL, October 8, 200718 Conclusions: pPDFs have evolved dramatically: pSIDIS opens a window to sea quarks and helps to constrain other densities dependence on FFs as a caveat: future prospects: successfull experimental programs tools for the analysis (NLO) from ‘scenarios’ to ‘constraints’ overall picture combined NLO global fits: consistency pDIS/pSIDIS improved constraints on pPDFs best fits favor small Δg and SU(3)? needs improvement! encouraging! new polarized data: RHIC, COMPASS, JLAB, eRHIC? new generation of FFs most exciting in the spin saga: the unexpected…

19. R. Sassot BNL, October 8, 200719 Acknowledgments: A. Deshpande, W. Vogelsang RIKEN-BNL, hospitality and support.

20. R. Sassot BNL, October 8, 200720

21. R. Sassot BNL, October 8, 200721

22. R. Sassot BNL, October 8, 200722

23. R. Sassot BNL, October 8, 200723 Results: 478-20=458 d.o.f 313 pDIS 165 pSIDIS Interplay between pDIS and pSIDIS D. de Florian, G. Navarro, R.S. Phys.Rev.D71 094018 (2005)