Double parton interaction: the values of $\sigma_{\rm eff}$

Abstract

In this letter we show that the two parton showers mechanism for $J/\Psi$ production, that has been discussed in Ref.[28], leads to small values of $\sigma_{\rm eff}$ for the production of a pair of $J/\Psi$. We develop a simple two channel approach to estimate the values of $\sigma_{\rm eff}$, which produces values that are in accord with the experimental data.