# $\Psi(2s)$ production in $p+A$ collisions

## TL;DR

This paper analyzes $\psi(2s)$ production in proton-nucleus collisions using a modified QVZ model, accounting for nuclear effects and final state interactions, successfully describing existing data and predicting suppression at near-threshold energies.

## Contribution

The study introduces an adapted two-component QVZ model that incorporates nuclear modifications and final state interactions to accurately describe $\psi(2s)$ production in $p+A$ collisions.

## Key findings

- Model successfully describes existing $\psi(2s)$ production data.
- Nuclear modifications and final state interactions are crucial for accurate modeling.
- Predictions indicate $\psi(2s)$ suppression at near-threshold energies.

## Abstract

We have analyzed the data on $\psi'$ production in proton-nucleus ($p+A$) collisions, available from the NA50 Collaboration in the SPS energy domain. The investigated data sets include the absolute production cross sections as well as $\psi'$-to-Drell Yan (DY) cross section ratios. An adapted version of two component QVZ model has been employed to calculate $\psi'$ production cross sections. For both $\psi'$ and DY production, nuclear modifications to the free nucleon structure functions are taken into account. For $\psi'$, final state interaction of the produced $c\bar{c}$ pairs with the nuclear medium is also taken into account, in accordance with the previously analyzed $J/\psi$ data. A satisfactory description of the data in $p+A$ collisions is obtained. Model calculations are extrapolated to low energy regime to predict the $\psi'$ suppression in proton induced collisions at near threshold energies.