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Selection of ZEUS results

Selection of ZEUS results. Halina Abramowicz. hadronic final states heavy flavors energy dependence of  tot ( * p) diffraction inclusive DIS measurement (H1/ZEUS F 2 and PDFs) F L determination. HERA Luminosity. Available luminosity HI HII

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Selection of ZEUS results

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  1. Selection of ZEUS results Halina Abramowicz • hadronic final states • heavy flavors • energy dependence of tot(*p) • diffraction • inclusive DIS measurement (H1/ZEUS F2 and PDFs) • FL determination DIS08

  2. HERA Luminosity Available luminosity HI HII (pb-1) HER Ep=920 GeV e+p 125 190 e-p 19 210 MER Ep=575 GeV e+p 8 LER Ep=460 GeV e+p 14 Polarised e+, e- (P0.30) HERA stopped operation on June 30, 2007 DIS08

  3. QPM QCDC - large x BGF - low x Hadronic final states - Jets Usually source of information about S In CC also sensitivity to quark flavors DIS08

  4. Inclusive jets in CC ep NLO - MEPJET with ZEUS-S PDFs PDF uncertainties included e- e+ e-/e+ DIS08

  5. Hadronic final states - Hunt for glueballs All Q2 data mostly Q2<1 GeV2 • Fit M and  of 4 resonances • Include interference for 2+ states (SU(3) symmetry) • 2/ndf=86/97 Nf0(1710)=4058820 (5) candidate for glueball (0+) • fit without f02/ndf=162/97 DIS08

  6. Hadonic final states - • f0 also seen in TASSO/L3 - cannot be pure glue state • masses lower than PDG (includes other measurements) • widths agrees with PDG DIS08

  7. Heavy flavor production Charm, beauty production with sensitivity to • gluons • pQCD (various mass schemes) • not included in PDFs DIS08

  8. Heavy flavors production b  e+jet b   DIS08

  9. Beauty production Latest summary DIS08

  10. Exclusive beauty production 10421 events 1998-2007 ZEUS data with Ep=920GeV integrated luminosity 410pb-1 5 signal from (1S), (2S), (3S) DIS08

  11. Exclusive processes soft hard hard soft DIS08

  12. W dependence of tot(p) What does it mean soft? Donnachie Landshoff Cudell et al. (after rejecting some data) DIS08

  13. W dependence of tot(p) Minimal trigger in CAL HER 920 GeV Subtract overlays p LER 460 GeV e 27.5 GeV Calibrate 6mT with BH Detect scattered electron Q20, measure energy ZEUS preliminary DIS08

  14. Inclusive diffraction • Large fraction of DIS events have LRG (visible 10%) DGLAP LRG cannot be generated by DGLAP. Maybe it is there in the initial condition? DIS08

  15. Inclusive diffraction - selection LPS method Selection methods Difference in proton dissociation and statistics Mx method xL = pz’/pz Large Rapidity Gap (LRG) method DIS08

  16. Inclusive diffraction - normalisation Pythia tuned to FPC and LPS (xL<0.90) DIS08

  17. Inclusive diffraction - comparison H1=LRG (MY<1.6 GeV) · 0.87 LRG(MN=Mp)=MX(MN<2.3 GeV)· 0.83 DIS08

  18. Inclusive diffraction in DIS soft vs hard Inclusive diffraction in DIS comes out to be a soft phenomenon, even at large Q2 • LPS/LRG Regge fit • W-dep. of D Cudell et al. ZEUS(prel.) DIS08

  19. F2 and PDFs - HERA I H1/ZEUS combined DIS08

  20. F2 and PDFs - HERA I H1/ZEUS combined Systematic uncertainty greatly reduced when data combined DIS08

  21. F2 and PDFs - HERA I H1/ZEUS combined Note MSTW08 is as yet unpublished - a prerelease DIS08

  22. F2 and PDFs - HERA I H1/ZEUS combined xdV xuV xS xg DIS08

  23. High Q2 - a taste of future Electroweak couplings of light quarks (using e-L,R) Global QCD fit e- ZEUS limit on quark Rq<0.62 10-16 cm LEP limit on electron Re<0.28 10-16 cm DIS08

  24. FL - measurement principle fixed x,Q2 • Sensitivity to FL requires high y • Challenge - high y means low electron • energy and large background from p • Need additional tools - use CTD/MVD hit information - use 6mT to normalise p High s - Ep=920 GeV Low s - Ep=460 GeV Medium s - Ep=575 GeV , not reported here DIS08

  25. FL - control plots 920 GeV 460 GeV MC FL=0 N(p)<15% DIS08

  26. Reduced cross section as a function of x,Q2 DIS08

  27. Reduced cross section as a function of x,Q2 DIS08

  28. Reduced cross section as a function of x,Q2 DIS08

  29. FL DIS08

  30. Summary Those are exciting times Many more results and many more details will be presented in the parallel sessions DIS08

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