IR-Renormalon Contributions to the Structure Functions g3g_3 and g5g_5

We calculate the leading $1/N_f$ perturbative contributions to the polarized nonsinglet structure functions $g_3$ and $g_5$ to all orders in $\alpha_s$. The contributions from the first renormalon pole are determined. It is a measure for the ambiguity of the perturbative calculation and is assumed to dominate the power corrections. The corrections $\Delta g_3$ and $\Delta g_5$ are given as functions of the Bjorken variable $x$ and turn out to be negligable. The anomalous dimensions of the leading twist operators are obtained in the next-to-leading order.Comment: 12 pages, 4 eps-figure

Diffractive charged meson pair production

We investigate the possibility to measure the nonforward gluon distribution function by means of diffractively produced \pi^+\pi^- and K^+K^- pairs in polarized lepton nucleon scattering. The resulting cross sections are small and are dominated by the gluonic contribution. We find relatively large spin asymmetries, both for \pi^+\pi^- and for K^+K^- pairs.Comment: 15 pages, version with changed kinematical cuts, to be pubished in Phys.Lett.

Neutrino induced hard exclusive D_s production

Motivated by the possibility to use high intensity neutrino beams for neutrino-nucleon scattering experiments we analyze charged current induced exclusive meson production within the framework of generalized parton distributions. The cross section for hard exclusive D_s production is estimated in this formalism to leading order in QCD. The integrated cross section proves to be sizable. It is shown that the considered process is well suited to provide novel information on the gluon structure of nucleons, which is contained in the generalized gluon parton distribution.Comment: 7 pages; modified plots in Fig. 3; accepted for publication in Phys. Lett.

πη\pi\eta pair hard electroproduction and exotic hybrid mesons

We show that hard electroproduction is a promising way to study exotic hybrid mesons, in particular through the hybrid decay channel $H \to \pi\eta$. We discuss the $\pi\eta$ generalized distribution amplitude, calculate the production amplitude and propose a forward-backward asymmetry as a signal for the hybrid meson production.Comment: 4 pages, 1 figure, presented by I.V. Anikin at Xth International Conference "BARYONS'04", Palaiseau, Franc

Exclusive decay of 1−−1^{- -} heavy quarkonium into photon and two pions

We study the exclusive decay of $1^{--}$ heavy quarkonium into one photon and two pions in the kinematic region, where the two-pion system has a invariant mass which is much smaller than the mass of heavy quarkonium. Neglecting effects suppressed by the inverse of the heavy quark mass, the decay amplitude can be factorized, in which the nonperturbative effect related to heavy quarkonium is represented by a non-relativistic QCD matrix element, and that related to the two pions is represented by a distribution amplitude of two gluons in the isoscalar pion pair. By taking the asymptotic form for the distribution amplitude and by using chiral perturbative theory we are able to obtain numerical predictions for the decay. Numerical results show that the decay of \jpsi can be observed at BEPC and at CESR. Experiment observation of this process in this kinematic region at BEPC and CESR can provide information about how gluons are converted into the two pions and may supply a unique approach to study $I = 0$ s-wave $\pi \pi$ scattering.Comment: 9 pages, Latex file, 5 EPS figures, 1) Just before summarizing our work, a paragraph is added to clarify the contribution of D-wave pion pair. 2) one reference is added, 3) exponential factor in Eq.(2) is delete

Diffractive D_s production in charged current DIS

We present a perturbative QCD calculation of diffractive $D_s$ production in charged current deep inelastic scattering. In the two-gluon exchange model, we analyze the diffractive process \nu N \to \mu^- N \Ds, which may provide useful information for the gluon structure of nucleons and the diffraction mechanism in QCD. The cross section of diffractive $D_s$ production with \xBj=0.005-0.05 and $E_\nu=50$ Gev is found to be $2.7\times10^{-5}$ pb. In spite of this small cross section, the high luminosity available at the $\nu$-Factory in the future would lead to a sizable number of diffraction events.Comment: 6 pages, 5 eps figures, final version to appear in PL

Hunting the QCD-Odderon in hard diffractive electroproduction of two pions

Charge asymmetries in diffractive electroproduction of two mesons are proportional to the interference of Pomeron and Odderon exchange amplitudes. We calculate in the framework of QCD and in the Born approximation a forward-backward charge asymmetry which turns out to be sizable in a kinematical domain accessible to HERA experiments. We predict a distinctive dependence of this asymmetry on the invariant mass of the two pions. Testing this prediction is a crucial step in the discovery of the QCD-Odderon.Comment: 13 pages LATEX, 6 .eps figures, numerical error corrected, new figures,main conclusions not change