# Dipole evolution: perspectives for collectivity and $\gamma^*$A collisions

## TL;DR

This paper investigates the proton's transverse structure and its evolution using dipole models, aiming to improve understanding of collectivity in high energy collisions and develop tools for future electron-ion collider simulations.

## Contribution

It introduces predictions of eccentricities and fluctuations in proton structure via dipole BFKL evolution and explores initial state colour fluctuations for exclusive $oldsymbol{ ext{γ}^* ext{A}}$ collision modeling.

## Key findings

- Predicted eccentricities and fluctuations in proton structure.
- Assessed the role of colour fluctuations in initial states.
- Model parameters fitted to ep and pp collision data.

## Abstract

The transverse, spatial structure of protons is an area revealing fundamental properties of matter, and provides key input for deeper understanding of emerging collective phenomena in high energy collisions of protons, as well as collisions of heavy ions. In this paper eccentricities and eccentricity fluctuations are predicted using the dipole formulation of BFKL evolution. Furthermore, first steps are taken towards generation of fully exclusive final states of $\gamma^*$A collisions, by assessing the importance of colour fluctuations in the initial state. Such steps are crucial for the preparation of event generators for a future electron-ion collider. Due to the connection between an impact parameter picture of the proton structure, and cross sections of ep and pp collisions, the model parameters can be fully determined by fits to such quantities, leaving results as real predictions of the model.