Investigating the pion emission source in pp collisions using the AMPT model with sub-nucleon structure

TL;DR

This study uses the AMPT model with sub-nucleon structure to analyze pion emission sources in high-multiplicity pp collisions at 13 TeV, revealing scaling behaviors similar to heavy-ion collisions and enhancing understanding of small-system interferometry.

Contribution

The paper introduces a systematic analysis of pion source functions in pp collisions using the AMPT model with sub-nucleon structure, reproducing experimental t scaling and source radii.

Findings

AMPT model reproduces t scaling in pp collisions.

Pion emission source radii match ALICE measurements.

Sub-nucleon structure is crucial for accurate modeling.

Abstract

The measurement of momentum correlations of identical pions serves as a fundamental tool for probing the space-time properties of the particle emitting source created in high-energy collisions. Recent experimental results have shown that, in pp collisions, the size of the one-dimensional primordial source depends on the transverse mass (\mt) of hadron pairs, following a common scaling behavior, similar to that observed in Pb--Pb collisions. In this work, a systematic study of the \pipi source function and correlation function is performed using the multiphase transport model (AMPT) to understand the properties of the emitting source created in high multiplicity pp collisions at $\sqrt{s}=13$ TeV. The \mt scaling behavior and pion emission source radii measured by ALICE experiment can be well described the model with sub-nucleon structure. These studies shed new light on the understanding of the effective size of the \pipi emission source and on studying the intensity interferometry in small systems with a transport model.