One-loop corrections to the processes $e^+e^- \to \gamma, Z \to J/\psi~\eta_c$ and $e^+e^- \to Z \to J/\psi~J/\psi$

TL;DR

This paper calculates one-loop quantum corrections to specific charmonium production processes in electron-positron collisions near the Z boson resonance, revealing significant increases in predicted cross sections at the Z mass.

Contribution

It provides the first detailed one-loop (NLO) estimates of $J/ au$ and $J/ au$ production cross sections in $e^+e^-$ annihilation near the Z pole, including both photon and Z boson contributions.

Findings

NLO corrections increase cross sections by a factor of 3.5 at Z mass.

Both $ ext{γ}$ and Z boson contributions are significant.

Results are relevant for experimental measurements at high-energy colliders.

Abstract

The cross section values of $J/\psi\ \eta_c$ and $J/\psi\ J/\psi$ production in $e^+e^-$ annihilation are estimated within one-loop approximation near $Z$ pole, as well as at higher energies. Both intermediate bosons, $\gamma$ and $Z$, are taken into account. It is shown that at $Z$ mass the NLO contribution increases the cross-section values by 3.5 times.