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NNPZ, GLM, FKS, GBW, MMS DGKP, BGBK, IIM, FSS…… KT - Kowalski, Teaney

Saturation Model for exclusive processes at HERA, DVCS, F2, including evolution and impact parameter dependence Henri Kowalski DESY DIS 2007 Munich, 17 th of April 2007. NNPZ, GLM, FKS, GBW, MMS DGKP, BGBK, IIM, FSS…… KT - Kowalski, Teaney KMW - Kowalski, Motyka, Watt. Dipole Models

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NNPZ, GLM, FKS, GBW, MMS DGKP, BGBK, IIM, FSS…… KT - Kowalski, Teaney

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  1. Saturation Model for exclusive processesat HERA, DVCS, F2,including evolution and impact parameter dependenceHenri KowalskiDESY DIS 2007Munich, 17th of April 2007

  2. NNPZ, GLM, FKS, GBW, MMS DGKP, BGBK, IIM, FSS…… KT - Kowalski, Teaney KMW - Kowalski, Motyka, Watt Dipole Models equivalent to LO perturbative QCD for small dipoles Glauber Mueller Optical Theorem proton shape KT

  3. KMW Total g*p cross-section KT ltot universal rate of rise of all hadronic cross-sections x < 10-2 b-Sat b-CGC

  4. Dipole Model - gluon density convoluted with dipole wave functions simultaneous prediction/description of many reactions -LPS Inclusive Diffraction KT BGBK F2 C Inclusive Diffraction

  5. Diffractive Di-jets Q2 > 5 GeV2 -RapGap Satrap

  6. Exclusive Vector Meson Production H. Kowalski, L. Motyka, G. Watt Effective modification of Fourier Trans by Bartels, Golec-Biernat, Peters Real part correction Skewedness correction Martin, Ryskin Teubner

  7. Wave Functions WF Overlaps Boosted Gaussian – NNPZ, FKS, FS Gaussian distribution of quark 3-momentum in the meson rest frame then boosted to LC Gauss LC - KT Gaussian distribution of quark 2-momentum in LC, factorization of r, z components - strong endpoint suppression infT Parameters of WF fixed by normalization conditions and the values of mesons decay constant, fV

  8. from gluon density convoluted with dipole wave functions we obtain simultaneous prediction/description of many reactions DVCS Vector Mesons KMW Note: educated guesses for VM wf work surprisingly well

  9. KMW evolution of a saturated gluon density Rates of rise of the VM cross-sections At EIC it should be possible to reduce the errors by a large factor, O(100),  study of t-dependent rate of rise  study of b-dependent Pomeron evolution – direct insight into saturation inside the proton or nuclei

  10. KMW properties of wave functions Ration of longitudinal/transverse x-sections

  11. Exponential fall of t-distributions  gaussian shape of the proton in the impact parameter b

  12. Description of the size of interaction region BD Modification by Bartels, Golec-Biernat, Peters KMW BG BG the gluonic proton radius smaller than the quark radius

  13. t-distributions of DVCS

  14. What have we learnt from HERA about small-x Rate of rise of the g*p cross-section In the impact parameter dipole models of DIS with the gaussian proton shape the fit of the rate of rise of sg*p requires QCD evolution which is DGLAP-like DGLAP-like  strong interdependence between l and Q2 universal rate of rise of all hadronic cross-sections median Large fraction of sg*p comes from the region of large b where matter density is low

  15. Saturation scale (a measure of gluon density at which gluon re-scattering starts to be substantial) HERA RHIC QSRHIC (x=10-2) ~ QSHERA(x=10-4)

  16. Is saturated state observed at HERA perturbative? universal rate of rise of all hadronic cross-sections

  17. properties gluon density Random walk in the impact parameter

  18. Study of the Glue t-distributions for exclusive diffractive meson production on proton and nuclei at EIC first estimate of the expected measurement precision: DpT < 30 MeV, t ~ pT2 Dt < 0.01 GeV2 for proton and light nuclei

  19. What are the lessons/open questions for EIC from exclusive diffraction at HERA Precise study of gluon density, tested with dipoles of various sizes, measure gluon diffusion evolution effects Diffractive vector mesons scattering - an excellent probe of nuclear matter, why is the gluonic radius smaller than the quark radius?? >>>>> Measure t distribution on (polarized) nuclei <<<<<< >>>>> Obtain holographic picture of nuclei !!!! <<<<<<

  20. BGBK – DGLAP evolution & saturation GBW - saturation only

  21. More about saturation with impact parameter without impact parameter

  22. properties of the gluon density Rise of the DVCS cross-sections

  23. Smooth Gluon Cloud Q2 (GeV2) C 0.74 1.20 1.70 Ca 0.60 0.94 1.40

  24. Hard Diffraction – the HERA surprise Non-Diffractive Event Diffractive Event expected before HERA <0.01%, seen over 10% at Q2=10 GeV2 Diffraction at HERA is so large because it is a shadow of DIS (i.e. inelastic processes)  dipole picture

  25. A glimpse into nuclei Naïve assumption for T(b): Wood-Saxon like, homogeneous, distribution of nuclear matter

  26. DIS on Nuclei

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