Entropy, purity and gluon cascades at high energies with recombinations and transitions to vacuum

TL;DR

This paper extends dipole cascade models in high-energy QCD to include vacuum transitions, successfully describing LHCb multiplicity data and revealing new scaling regimes and quantum information properties.

Contribution

It introduces a generalized cascade model with vacuum transitions, linking it to the Negative Binomial Distribution and exploring new scaling regimes and quantum information aspects.

Findings

Cascade models can be related to Negative Binomial Distribution.

Including vacuum transitions improves data description.

Identification of 'focal' and 'parallel' regimes.

Abstract

We study one dimensional dipole cascade models in the high-energy limit of QCD. Motivated by data on hadron multiplicities in the LHCb kinematical range, we generalize existing cascade models for splitting and recombination to account also for transitions to the vacuum. This modification allows us to describe the data. Furthermore, we perform both analytical and numerical studies of the cascades and find that the cascade including loop corrections, as well as the one accounting for transitions to the vacuum, can both be related to the Negative Binomial Distribution. In the latter case, however, one must properly normalize the cascade to account for transitions to the vacuum. We also study the scaling properties of the cascades and identify new regimes, which we call "focal" and "parallel." Finally, we investigate the Quantum Information (QI) measures of the cascades, which allow us to highlight their distinctive properties.