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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.
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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
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
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
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
QCD: Collinear vs high-energy factorization DDIS= Diffractive Deep Inelastic Scattering
The upper impact-factors, longitudinal polarized photon Pomeron pQCD- calculation Odderon
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
Which resonances contribute? O-exchange only C=+ and I=0 possible P-exchange only C=- and I=1 possible
The 2-pion-distribution-amplitudes, continued Kühn/Santamaria, Z.Phys. C48, 1990, Hyams et al., Nucl.Phys. B64,1973
The lower impact-factors according to Gunion/Soper, Phys.Rev.D15, 1977 and Fukugita/Kwiecinski, Phys.Lett.B83, 1979 model-dependent
The charge asymmetry specific m2 -dependence
The spin asymmetry complementary m2-dependence
Some numerical results longitudinal polarization
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
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!
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
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?