Exclusive and dissociative J/Ψ production with collinear-improved Balitsky-Kovchegov equation

We extend the hotspot model to include the virtuality dependence and use it to study the exclusive and dissociative J/psi production combined with the dipole amplitude in the target rapidity representation. We determined that virtuality takes effect on a number of hotspots, thus providing a better description of the J/psi production data at HERA. The collinear improved Balitsky-Kovchegove equation in the target rapidity representation is numerically solved and used to fit the J/psi experimental data with a series of hotspot sizes. We infer that virtuality significantly influences the number and size of hotspots. The expression chi(2)/d.o.f = 1.0183 resulting from the fit with the collinear improved dipole amplitude in the target rapidity representation is more reasonable than the corresponding chi(2)/d.o.f = 1.3995 originating from the leading order fit, which indicates that the collinear improved evolution equation in the target rapidity representation can provide a relatively good depiction of the exclusive and dissociative HERA data.