Emission source functions in heavy ion collisions

TL;DR

This paper uses the HKM model to analyze three-dimensional pion and kaon emission source functions in heavy ion collisions, successfully reproducing experimental data and exploring the effects of rescatterings and resonances on source tails.

Contribution

It provides a detailed simulation-based analysis of emission source functions, including long-range tails and emission times, and predicts source functions for LHC energies.

Findings

HKM reproduces non-Gaussian tails in source functions

Rescatterings mainly contribute to the out tail

Substantial emission times are observed for pions

Abstract

The three-dimensional pion and kaon emission source functions are extracted from the HKM model simulations of the central Au+Au collisions at the top RHIC energy $\sqrt{s_{NN}}=200$ GeV. The model describes well the experimental data, previously obtained by the PHENIX and STAR collaborations using the imaging technique. In particular, the HKM reproduces the non-Gaussian heavy tails of the source function in the pair transverse momentum (out) and beam (long) directions, observed in the pion case and practically absent for kaons. The role of the rescatterings and long-lived resonances decays in forming of the mentioned long range tails is investigated. The particle rescatterings contribution to the out tail seems to be dominating. The model calculations also show the substantial relative emission times between pions (with mean value 14.5 fm/c in LCMS), including those coming from resonance decays and rescatterings. The prediction is made for the source functions in the LHC Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV, which are still not extracted from the measured correlation functions.