Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Subthreshold poles in electron-positron annihilation. D\bar{D} final states

Peter Lichard

TL;DR

The study shows that a subthreshold pole, likely associated with the $\psi(2S)$, significantly influences $e^+e^-$ annihilation into $D\bar D$ final states. Using a vector-meson-dominance framework with multiple resonances, the authors merge BESIII and BES data to fit the cross sections, finding a SP with high statistical significance ($8.2\sigma$) near the $D\bar D$ threshold. Allowing for seven resonances in addition to the SP yields a best-fit with $\chi^2/\mathrm{NDF}=240.4/284$ and $p=97\%$, suggesting the need to include SPs to accurately describe the data. The analysis also identifies known and speculative resonances in the 3.8–4.6 GeV region and reinforces the role of SPs in shaping hadronic cross sections in $e^+e^-$ annihilation, with implications for charmonium spectroscopy.

Abstract

We show that the $ψ(2\mathrm S)$ subthreshold pole influences the cross section of the electron-positron annihilation into the $\mathrm D^+\mathrm D^-$ and $\mathrm D^0\bar\mathrm D^0$ final states. We perform a fit to the merged BES \cite{bes2008} and BESIII \cite{besiii2024} data, providing the cross section for $e^+e^-$ annihilation into those final states. The statistical significance of the $ψ(2\mathrm S)$ as a subthreshold pole is 8.2$σ$. A fit assuming it and seven resonances excels with the fit quality characterized by $χ^2/\mathrm{NDF}=240.4/284$, which means a $p$-value of 97\%.

Subthreshold poles in electron-positron annihilation. D\bar{D} final states

TL;DR

The study shows that a subthreshold pole, likely associated with the , significantly influences annihilation into final states. Using a vector-meson-dominance framework with multiple resonances, the authors merge BESIII and BES data to fit the cross sections, finding a SP with high statistical significance () near the threshold. Allowing for seven resonances in addition to the SP yields a best-fit with and , suggesting the need to include SPs to accurately describe the data. The analysis also identifies known and speculative resonances in the 3.8–4.6 GeV region and reinforces the role of SPs in shaping hadronic cross sections in annihilation, with implications for charmonium spectroscopy.

Abstract

We show that the subthreshold pole influences the cross section of the electron-positron annihilation into the and final states. We perform a fit to the merged BES \cite{bes2008} and BESIII \cite{besiii2024} data, providing the cross section for annihilation into those final states. The statistical significance of the as a subthreshold pole is 8.2. A fit assuming it and seven resonances excels with the fit quality characterized by , which means a -value of 97\%.

Paper Structure

This paper contains 7 sections, 10 equations, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. Model
  3. The explored data
  4. A subthreshold pole appearing
  5. Results
  6. Conclusions
  7. Derivation of formula (\ref{['sigma']})

Figures (4)

  • Figure 1: Feynman diagram defining our model
  • Figure 2: The $e^+e^-\rightarrow\mathrm D^+\mathrm D^-$ cross section as it follows from the joint fit to both processes assuming the $\psi(2\mathrm S)$ SP with seven resonances, summarized in Table \ref{['tab:duo_parms']}.
  • Figure 3: The $e^+e^-\rightarrow\mathrm D^0\bar{\mathrm} D^0$ cross section as it follows from the joint fit to both processes assuming the $\psi(2\mathrm S)$ SP with seven resonances, summarized in Table \ref{['tab:duo_parms']}.
  • Figure 4: Comparison of the resonances found here (marked with simple numerals) with those in the PDG 2024 tables, distinguished by short lines at endpoints.