The cross section of the process $e^+e^- \to p\bar{p}$ in the vicinity of charmonium $\psi(3770)$ including three-gluon and $D$-meson loop contributions

TL;DR

This paper calculates the cross section of the process $e^+e^- o par{p}$ near the $ ext{psi}(3770)$ resonance, highlighting the dominant three-gluon mechanism and its impact on the phase and shape of the cross section.

Contribution

It introduces a detailed calculation of the cross section including three-gluon and D-meson loop contributions near the $ ext{psi}(3770)$ resonance, emphasizing the role of the three-gluon mechanism.

Findings

Three-gluon mechanism dominates the cross section.

The phase from the three-gluon contribution causes a dip in the cross section.

D-meson loop contribution is relatively small.

Abstract

The total cross section of the process $e^+e^- \to p\bar{p}$ is calculated within the energy range close to the mass of $\psi(3770)$ charmonium state. It was shown that the main contribution to this cross section comes from three gluon mechanism which is also responsible of the large phase with respect to the Born amplitude. This phase provides the characteristic dip behaviour of the cross section in contrast to the usual Breit-Wigner peak shape. OZI-allowed mechanism with D-mesons in the intermediate state was also estimated and gives relatively small contribution to the cross section and to the phase.