Reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- at energies \sqrt{s}\leq 1 GeV

TL;DR

This study calculates the cross section of the e^+e^- to four-pion reaction within 0.65 to 1 GeV using a generalized hidden local symmetry model, highlighting the importance of heavy isovector resonances for data agreement.

Contribution

It introduces the inclusion of heavy isovector resonances ho(1450) and ho(1700) into the model, improving the match with experimental data at energies up to 1 GeV.

Findings

Heavy resonances significantly contribute at \sqrt{s} \\approx 1 GeV.

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

Resonances account for 30-60% of the ho(770) contribution at their peak energies.

Abstract

The cross section of reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- is calculated for energies 0.65\leq \sqrt{s}\leq1 GeV in the framework of the generalized hidden local symmetry model. The calculations are compared with the 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 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.