# Correlations in ultra-relativistic nuclear collisions with strings

## TL;DR

This paper investigates how fluctuations in string end-points in models of ultra-relativistic nuclear collisions affect rapidity spectra and correlations, helping to better understand initial state radiation.

## Contribution

It introduces a generic model with fluctuating string end-points and analyzes different scenarios against experimental data to discriminate among possible initial state configurations.

## Key findings

- String-end-point fluctuations influence rapidity spectra.
- Experimental data constrains possible fluctuation scenarios.
- Correlations help discriminate between different string models.

## Abstract

While string models describe initial state radiation in ultra-relativistic nuclear collisions well, they mainly differ in their end-point positions of the strings in spatial rapidity. We present a generic model where wounded constituents are amended with strings whose both end-point positions fluctuate and analyze semi-analytically various scenarios of string-end-point fluctuations. In particular we constrain the different cases to experimental data on rapidity spectra from collisions at $\sqrt{s_{\rm NN}}=200$~GeV, and explore their respective two-body correlations, which allows to partially discriminate the possible solutions.