Hidden local symmetry and the reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- at energies \sqrt{s}\leq 1 GeV

TL;DR

This paper uses a generalized hidden local symmetry model to calculate the e^+e^- to 4-pion reaction cross-section between 0.65 and 1 GeV, emphasizing the importance of heavy resonances for data agreement.

Contribution

It introduces a generalized hidden local symmetry approach to describe meson interactions and accurately predicts the reaction cross-section, highlighting the role of heavy isovector resonances.

Findings

Heavy resonances ho(1450) and ho(1700) are essential for matching experimental data.

Resonance contributions at 1 GeV are 30 times larger than ho(770).

Resonance effects constitute 30-60% of the ho(770) contribution at \

Abstract

Based on the generalized hidden local symmetry as the chiral model of pseudoscalar, vector, and axial vector mesons, the excitation curve of the reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- is calculated for energies in the interval 0.65\leq \sqrt{s}\leq1 GeV. The theoretical predictions are compared to available data of CMD-2 and BaBaR. It is shown that the inclusion of heavy isovector resonances \rho(1450) and \rho(1700) is necessary for reconciling calculations with the data. It is found that at \sqrt{s}\approx1 GeV the contributions of the above resonances are much larger, by the factor of 30, than the \rho(770) one, and are amount to a considerable fraction \sim0.3-0.6 of the latter at \sqrt{s}\sim m_\rho.