Balance Function in High-Energy Collisions

Abstract EN

Aspects and implications of the balance functions (BF) in high-energy physics are reviewed.

Thevarious calculations and measurements depending on different quantities, for example, system size, collisionscentrality, and beam energy, are discussed.

First, the different definitions including advantages andeven short-comings are highlighted.

It is found that BF, which are mainly presented in terms ofrelative rapidity, and relative azimuthal and invariant relative momentum, are sensitive to the interactioncentrality but not to the beam energy and can be used in estimating the hadronization time and thehadron-quark phase transition.

Furthermore, the quark chemistry can be determined.

The chemicalevolution of the new-state-of-matter, the quark-gluon plasma, and its temporal-spatial evolution,femtoscopy of two-particle correlations, are accessible.

The production time of positive-negativepair of charges can be determined from the widths of BF.

Due to the reduction in the diffusiontime, narrowed widths refer to delayed hadronization.

It is concluded that BF are powerful toolscharacterizing hadron-quark phase transition and estimating some essential properties.