Possible probe of the QCD odderon singularity through the quasidiffractiveηcproduction in γγ collisions

Abstract

The reactions $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}{\ensuremath{\eta}}_{c}{\ensuremath{\eta}}_{c}$ and $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}{\ensuremath{\eta}}_{c}+X$ are discussed within the three-gluon-exchange model. We give predictions for the differential cross sections and discuss the feasibility of measuring these processes at CERN LEP2 and Cornell TESLA. The total cross sections were estimated to be approximately equal to 40 fb and 120 fb for $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}{\ensuremath{\eta}}_{c}{\ensuremath{\eta}}_{c}$ and $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\gamma}}{\ensuremath{\eta}}_{c}+X,$ respectively, assuming exchange of elementary gluons that corresponds to the odderon with intercept equal to unity. These values can be enhanced by a factor equal to 2.4 and 2.9 for LEP2 and TESLA energies if the odderon intercept is equal to 1.07. The estimate of cross sections $\ensuremath{\sigma}{(e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\eta}}_{c}{\ensuremath{\eta}}_{c})$ and $\ensuremath{\sigma}{(e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}{\ensuremath{\eta}}_{c}X)$ for antitagged ${e}^{+}$ and ${e}^{\ensuremath{-}}$ is also given.