Investigating Notions of Entropy and Its Production in High Energy Particle Collisions

TL;DR

This paper explores various concepts of entropy and their production mechanisms in high-energy particle collisions, emphasizing quantum entanglement and decoherence effects during the early collision stages, using advanced analytical and phenomenological methods.

Contribution

It introduces new analytical approaches to calculate entanglement entropy in high-energy collisions and compares different entropy notions in dense gluonic states.

Findings

Entanglement entropy calculated for high-energy collisions at RHIC, Tevatron, and LHC energies.

Dynamic entropy in QCD gluonic states analyzed and contrasted with decoherence entropy.

Results highlight the significance of quantum effects in entropy production during early collision stages.

Abstract

This work analyzes different notions of entropy and its production in $ep$ and heavy-ion collisions, focusing on the early stages of the collision. To this end, the importance of phenomena such as quantum entanglement and decoherence in entropy generation was studied. Using state-of-the-art methods for calculating entanglement entropy in the high-energy limit and synthesizing various approaches for its computation, phenomenological results were obtained from analytical expressions for the number of gluons. Results were also presented for the entanglement entropy in two-body elastic scattering based on the hadronic structure given by the model-independent L\'evy method, at energy values typical of the RHIC, Tevatron, and LHC. Phenomenological models of unintegrated gluon distributions were used to calculate dynamic entropy in the QCD of dense gluonic states in $pp$ and $pA$ collisions at high energies, comparing it with decoherence entropy. The obtained results were contrasted with other notions of entropy in the literature, and theoretical uncertainties were discussed.