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Selection of ZEUS results

This summary explores ZEUS experimental findings related to heavy flavor production, hadronic final states, and inclusive measurements in Deep Inelastic Scattering (DIS) at the HERA collider. The focus is on energy dependence of total cross-sections, the identification of glueball candidates, and the nuances in quark flavor sensitivities through various production channels. The results leverage existing data from HERA, including luminosity insights and recent analyses in diffraction phenomena. These findings have significant implications for understanding QCD dynamics and the structure of matter.

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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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