Speaker
Description
We investigate the momentum transfer dependence of differential cross sections $d\sigma/dt$ in diffractive electroproduction of heavy quarkonia.
The calculations have been performed within the light-front QCD dipole formalism using realistic quarkonium wave functions determined from various potential models in the $Q\bar Q$ rest frame.
Model predictions for $d\sigma/dt$ including a proper correlation between the impact parameter $\vec b$ of a collision and color dipole orientation $\vec r$ are compared with available HERA data.
We analyze the impact of a realistic $\vec b$-$\vec r$ correlation on results for $d\sigma(t)/dt$ by comparing with conventional dipole models including only additional factorized $b$- dependent part and with recent calculations based on a popular Balitzky-Kovchegov model, where such a correlation is not incorporated accurately.
We have demonstrated that the effect of $\vec b$-$\vec r$ correlation is boosted in the production of radially excited charmonia due to the nodal structure of their radial wave functions.
Experimental investigation of the $\psi'(2S)$-to-$J/\psi(1S)$ ratio of $t$-dependent differential cross sections can shed more light on the onset of $\vec b$-$\vec r$ correlation within various dipole models, as well as on manifestation of saturation effects at small $x$.
