Final-state interaction in the process $e^{+}e^{-}\rightarrow\Lambda_{c}\bar{\Lambda}_{c}$

TL;DR

This paper demonstrates that final-state interactions, including tensor forces and Coulomb effects, explain the energy dependence of the $e^{+}e^{-} ightarrow\Lambda_{c}ar{\Lambda}_{c}$ cross section near threshold, challenging common assumptions.

Contribution

It introduces a detailed analysis of the role of tensor interactions and Coulomb potential in the near-threshold behavior of charmed baryon pair production.

Findings

Final-state interactions explain the observed energy dependence.

Tensor interactions cause mixing of S-wave and D-wave components.

Coulomb effects are significant only within a few MeV above threshold.

Abstract

We show that the final-state interaction explains the nontrivial near-threshold energy dependence of the cross section of the process $e^{+}e^{-}\rightarrow\Lambda_{c}\bar{\Lambda}_{c}$ observed by the Belle and BESIII collaborations. This energy dependence is the result of the mixture of $S$-wave and $D$-wave components of the $\Lambda_{c}\bar{\Lambda}_{c}$ wave function due to a tensor interaction. The Coulomb potential is important only in the narrow energy region about a few MeV above the threshold of the process. It is shown that the widely used assumption that the impact of the Coulomb interaction on the cross sections of hadron production is reduced to the Sommerfeld-Gamow-Sakharov factor is not correct.