Hadronic returns to the Z in electron-positron annihilation at high energy

TL;DR

This paper investigates a novel four-jet production mechanism in high-energy electron-positron collisions, focusing on the 'hadronic return' to the Z pole, which complements known QCD and electroweak processes.

Contribution

It provides a detailed analysis of the hadronic return process e+e- --> Z gg --> qqgg, highlighting its significance at high energies.

Findings

Identification of the hadronic return process as a distinct mechanism.

Quantitative estimates of its contribution at high energies.

Comparison with other four-jet production processes.

Abstract

The production of four hadronic jets in e+e- collisions above the Z pole is dominated by the QCD e+e- --> qqqq,qqgg processes and, for sufficiently high energy, the electroweak e+e- --> W+W- --> qqqq process. However there is another mechanism for producing four jets, e+e- --> Z gg --> qqgg, which can be regarded as a `hadronic return' to the Z pole. We investigate this new process in detail