1. 10.9.2002 MK @RADCOR02 Structure Functions at HERA Max Klein (H1, DESY Zeuthen) Status and Future RADCOR 02 Kloster Banz 10.9.2002 -Introduction -F2 at Low x -Measurement of alphas and xg -High Q2 -Quark Distributions -FL now and then -Summary no jets, spin klein@ifh.de

2. 10.9.2002 MK @RADCOR02 HERA ZEUS H1 positrons protons HERA -tunnel protons: 920 GeV positrons: 27.5 GeV circumference: 6.3 km

3. 10.9.2002 MK @RADCOR02 1992 introduction 1997 luminosity 0.2  20 pb-1 detector upgrades uncertainty 20%  2-3%

4. 10.9.2002 MK @RADCOR02 deep inelastic scattering at low x and Q2 most recent, 0.6pb-1 H1 DIS 02 Cracow low x

5. 10.9.2002 MK @RADCOR02 kinematic reconstruction BST SPACAL low x preliminary (H1) small photoproduction bgd: E-pz, BST track

6. 10.9.2002 MK @RADCOR02 low x

7. 10.9.2002 MK @RADCOR02 reduced cross section y<0.8 low x

8. 10.9.2002 MK @RADCOR02 Fractal Proton Structure – Self Similarity log dependence of (unintegrated parton) density fit to H197 low Q2 data and to ZEUS 97 BPT T.Lastovicka hep-ph/0203260 EPJ in print for 172 points, D2=1 low x

9. 10.9.2002 MK @RADCOR02 low x

10. 10.9.2002 MK @RADCOR02 QCD below its applicability low x ZEUS hep-ex/0208023

11. 10.9.2002 MK @RADCOR02 rise towards x  0 should have lowered Ee low x derivative independent of x for x<0.01 to within exp uncertainty PhysLett B520(01)183 H1 preliminary, DIS02, svx data 2000

12. 10.9.2002 MK @RADCOR02 PhysLett B520(01)183 derivative ~ lnQ2 still higher accuracy desirable low x

13. 10.9.2002 MK @RADCOR02 low x

14. 10.9.2002 MK @RADCOR02 exploring perturbative QCD alphas H1 EPJ C21(01)33

15. 10.9.2002 MK @RADCOR02 determination of the gluon momentum density to NLO H1 EPJ C21(01)33 fixed flavour nr scheme Laenen, Riemersma, Smith, vanNeerven need precision data at low Q2, all x! alphas

16. 10.9.2002 MK @RADCOR02 DIS measurement of alphas with H1 and BCDMS data alphas y(BCDMS) > 0.3 Q2(BCDMS) >7 GeV2  no NMC, E665  chi2+1 well defined is BCDMS correct?  low Ep run H1 EPJ C21(01)33 joint determination of alphas, xg, V,A F2 =xV/3 +11xA/9 = 4xU/9+xD/9 xg ~x bg

17. 10.9.2002 MK @RADCOR02 Results on the strong coupling constant hep-ex/0208023 alphas EPJ C21(01)33 H1 0.1150 +-0.0017(exp)+0.0009-0.0007(model) if: systematíc errors are not fitted: +0.0005 NMC replaces BCDMS 0.116+-0.003 (exp) 4 light flavours: +0.0003 BCDMS deuteron data added: 0.1158 +- 0.0016 (exp) large chi2 variations if Q2  (¼.. 4) Q2 renormalisation scale:+-0.005 (H1)  (1/2.. 2) : +- 0.004 (ZEUS) not included in error ZEUS 0.1166 +-0.0008(unc)+-0.0032(corr)+-0.0036(norm)+-0.0018(model) p:BCDMS,NMC,E665 d:NMC,E665 d/p: NMC xF3: CCFR systematíc errors are not allowed to vary in chi2 minimisation Q2>2.5 GeV2, W2>20GeV2, RTvfns, b(uv)=1/2, b(dv)=1/2 fit alphas, xg, uv, dv, sea, dbar-ubar (MRST) if fixed flavour scheme is used: +0.0010

18. 10.9.2002 MK @RADCOR02 electroweak unification in DIS K.Long ICHEP02 high Q2 full data 1994-2000

19. 10.9.2002 MK @RADCOR02 ICHEP02 H1 preliminaryhigh Q2

20. 10.9.2002 MK @RADCOR02 ICHEP02 H1 preliminaryhigh Q2

21. 10.9.2002 MK @RADCOR02 neutral currents at high x,Q2 high Q2 HERA 2 high Q2 simulation NC uncertainty ~2% CC uncertainty ~3% A.Mehta DIS01 HERA2: 10 times the luminosity of HERA1

22. 10.9.2002 MK @RADCOR02 exploratory measurements of xF3 H1: EPJ C19(2001)269; ZEUS: hep-ex/0208040 high Q2 direct access to valence quarks parity conserving e+ 100 pb-1 e- 15 pb-1 requires maximum possible luminosity

23. 10.9.2002 MK @RADCOR02 hep-ex/0208023. high Q2 CC data (ZEUS) high Q2 CC data not fitted

24. 10.9.2002 MK @RADCOR02 ICHEP02 prel. high Q2 CC data (H1) high Q2

25. 10.9.2002 MK @RADCOR02 MK high x Philadelphia 00 pdf e+, 250pb-1 e-, 250pb-1 simulation HERA2

26. 10.9.2002 MK @RADCOR02 A.Mehta DIS01. CC polarisation dependence high Q2 search for r.h. currents classic measurement, possible with modest luminosity but maximum polarisation

27. 10.9.2002 MK @RADCOR02 parity violation in F2 (gamma-Z) MK DIS01 Bologna high Q2

28. 10.9.2002 MK @RADCOR02 parton distribution functions from NLO QCD fits ZEUS hep-ex/0208023; H1 ICHEP02 pdf

29. 10.9.2002 MK @RADCOR02 parton distribution functions from NLO QCD fits (H1) H1 ICHEP02 pdf CC and NC cross sections are sensitive only to U, antiU, D,antiD (F2N has c-s admixture)  new H1 NLO QCD fit in which uv,dv,sea are replaced by the observables light flavours (xg consistent) possible with H1 data alone with assumption on sea symmetry

30. 10.9.2002 MK @RADCOR02 sea symmetry (simulation of ed) MK, DIS 02 pdf 40pb-1 ep 20pb-1 ed note (s-c)/3 =5/18 W2(cc)-F2N

31. 10.9.2002 MK @RADCOR02 up and down quarks at high Q2 ZEUS hep-ex/0208023; H1 ICHEP02 pdf

32. 10.9.2002 MK @RADCOR02 access to the longitudinal structure function FL H1 EPJ C21(01)33

33. 10.9.2002 MK @RADCOR02 determination of the longitudinal structure function FL H1: EPJ C21(01)33, DIS01 and ICHEP02 y<0.9 (this is E‘~2..3 GeV!) assumption on F2 more accurate data at large Q2 to come consistent with NLO QCD i.e. scaling violations of F2 limited to smallest x

34. 10.9.2002 MK @RADCOR02 FL simulation with lowered Ep FL MK Ringberg H1 internal 02: bins and Ep choices may be optimised 3..4 beam energies L ~ Ep systematics challenge smallest E‘ (BST: E/p) ultimate accuracy of ~5% Q2~1 GeV2: redo i.a.region

35. 10.9.2002 MK @RADCOR02 F2 charm FL ICHEP02 beauty to follow Silicon detectors vital

36. 10.9.2002 MK @RADCOR02 diffractive partons FL H1, DIS02

37. 10.9.2002 MK @RADCOR02 summary +Low x physics discovered as a new field of theoretical development and experimental fun + so far pQCD is consistent with structure function data but the ultimate precision of data and thy (N3LO) is still to be / is being approached (F2 1%, FL 5%, hiQ2 2% NC, 3% CC, about!) + F2c and F2D evolve towards precision testing grounds HERA1 HERA2 HERA3 + high luminosity, Silicon detectors, improved calibrations  large x, high Q2 (competetive searches) + NC,CC unfold pdf‘s, employ polarisation and charge dependence of cross sections, xg at high x?? + high accuracy, low Ep runs determine strong coupling constant with 1% accuracy and measure FL(x) + explore flavour decomposition at low x (eD) + discover saturation (eA) + understand confinement (better) + spin structure of the proton at low x and high Q2

38. 10.9.2002 MK @RADCOR02 ZEUS upgrades ZEUS expected to be operational in 2006 (U.Schneekloth at Durham) STTMVD new beam pipe

39. 10.9.2002 MK @RADCOR02 H1 upgrades major upgrades. H1 expected to be operational for years to come and follow – design 1986!

40. 10.9.2002 MK @RADCOR02 Workshops its time to conclude DESY directorate asks for proposals by end of 2003 Physics Ressources TESLA synch.radiation

41. 10.9.2002 MK @RADCOR02