# Signals for fluctuating constituent numbers in small systems

## TL;DR

This paper extends the TRENTo model to include fluctuating numbers of partons in nucleons, incorporating PDFs and momentum transfer dependence, to better understand initial conditions in heavy-ion collisions.

## Contribution

It introduces a novel sampling method for parton numbers based on PDFs within the TRENTo framework, accounting for momentum transfer effects.

## Key findings

- Distributions depend on momentum transfer and scale.
- Observable sensitivities to parton number fluctuations are analyzed.
- The model captures fluctuations in initial conditions more realistically.

## Abstract

We propose an extension of the initial condition model TRENTo for sampling the number of partons inside the nucleons that participate in a heavy-ion collision. This sampling method is based on parton distribution functions (PDFs) and therefore has a natural dependence on the momentum transferred in the collision and the scale being probed during the collision. We examine the resulting distributions and their dependence on the momentum transfer. Additionally, we explore the sensitivity of different observables on the number of partons using the TRENTo framework and the estimators available therein for final-state observables.