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Pomeron and Odderon Interference in Diffractive Meson Pairs Production

This study explores the interference effects of the Pomeron and Odderon in the production of diffractive meson pairs, focusing on the theoretical framework of perturbative QCD. We investigate the contributions of various gluon exchanges, the role of generalized parton distributions (GPDs), and specific asymmetries in hard diffractive electroproduction. The analysis includes insights from H1, ZEUS, HERMES, and COMPASS collaborations, highlighting how these processes can provide crucial information on the structure and dynamics of colorless states in quantum chromodynamics.

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Pomeron and Odderon Interference in Diffractive Meson Pairs Production

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  1. Pomeron/Odderon interference in diffractive meson pairs production Oleg Teryaev,BLTP, JINR, Dubna In collaboration with Philipp Hägler, MIT Bernard Pire,Ecole Polytechnique Lech Szymanowski,Ecole Polytechnique& Soltan Institute for Nuclear Studies, Warsaw Hägler/Pire/Szymanowski/Teryaev, Eur.Phys.J. C26:261-270,2002 and Phys.Lett. B535:117-126,2002

  2. Overview colorless flavourless Pomeron P Odderon O C-odd C-even effective theory pQCD: BFKL P/BKP O vs Generalized Partton Distr. (2,3)-gluon exchange GPD: + quark one! Reggeons P contributions are dominant pure O contributions are rather small Fracture functions=q,G distributions in P P/O=C/T-odd Fracture functions asymmetries in hard diffractive 2-pion electroproduction: Specifics of H1(ZEUS)/HERMES/COMPASS phase-shift dependence impact-factors Generalized (2-pion) distribution amplitudes

  3. Pomeron and Odderon  phenomenological Regge-approach perturbative QCD P and perturbative P predicts P/O-exchange predicts P/O-like 2/3-gluon-exchange ? O and perturbative O perturbative P/O

  4. Previous approaches to the O (non-exhaustive) underlying idea: C-Odd pQCD Ginzburg/Ivanov,Nucl.Phys.B388:376-390,1992 non-QCD Schäfer/Mankiewicz/Nachtmann,Phys.Lett.B2724,1991 Czyzewski/Kwiecinski/Motyka/Sadzikowski, Phys.Lett.B398, 1997 Engel/Ivanov/Kirschner/Szymanowski, Eur.Phys.J.C4, 1998 Bartels/Braun/Colferai/Vacca, Eur.Phys.J.C20,2000 pQCD non-QCD Brodsky/Rathsman/Merino, Phys.Lett.B461,1999 Ivanov/Nikolaev/Ginzburg,hep-ph/0110181, 0207345 non-QCD P/O-interference in hard diffractive pion-pair electroproduction in pQCD

  5. QCD: Collinear vs high-energy factorization DDIS= Diffractive Deep Inelastic Scattering

  6. The amplitudes

  7. The upper impact-factors, longitudinal polarized photon Pomeron pQCD- calculation Odderon

  8. The Generalized (2-pion) distribution-amplitudes Diehl/Gousset/Pire/Teryaev Phys.Rev.Lett..81,1782,1998 Gegenbauer-polynomials partial wave expansion dispersion relations evolution asymptotic expansion Diehl/Gousset/Pire, Phys.Rev.D62,073014,2000

  9. Which resonances contribute? O-exchange  only C=+ and I=0 possible P-exchange only C=- and I=1 possible

  10. The 2-pion-distribution-amplitudes, continued Kühn/Santamaria, Z.Phys. C48, 1990, Hyams et al., Nucl.Phys. B64,1973

  11. The lower impact-factors according to Gunion/Soper, Phys.Rev.D15, 1977 and Fukugita/Kwiecinski, Phys.Lett.B83, 1979 model-dependent 

  12. The charge asymmetry specific m2 -dependence

  13. The spin asymmetry complementary m2-dependence

  14. Some numerical results longitudinal polarization

  15. Higher order corrections & extra phases to LLA, -Pomeron-exchange is purely Im -Odderon-exchange is purely Re higher order corrections introduce additional phases non-resonant background

  16. Competing/supplementary processes Primakoff-contribution so far not calculated, estimated to be small Lehmann-Dronke/Schäfer et al.,Phys.Rev.D63(2001) collinear approach, off-forward scattering dominant/valid at „large“ x dies out at small x • predicted (without f0) rather well • large x data from HERMES • expected at COMPASS!

  17. asymmetry Lehmann-Dronke/Schäfer et al.,Phys.Rev.D63(2001) Reason-dominance of gluon GPD(C=-) HIGH twist is required Anisovich/Sarantsev,hep-ph/0203139

  18. Summary charge and spin asymmetries-sensitive test for C-T/odd Fracture Functions Pomeron/Odderon or various GPD‘s Complementarity of H1(ZEUS)/HERMES/COMPASS GPD -same GDA as in pQCD P/O -relatively small x – leading twist contribution to asymmetries go to zero (as ratio of quark/gluon GPD‘s) P/O -pQCD framework – large Q, small x -small Q (almost real photons)- COMPASS - phenomenological P/O?! a rather large asymmetry is predicted in the vicinity of the f0,2-resonances Outlook Higher twist C-odd gluonic GPD required (relation to O?!) more sophisticated GDAs/proton-impact-factors Kaon asymmetries Studies of f0 - resonance contribution to asymmetries- Key to its structure?

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