Parameter differences of the charged and neutral rho-meson family

TL;DR

This paper combines recent and older experimental data on pion form factors to precisely determine the parameters of charged and neutral rho-meson families, revealing their differences.

Contribution

It introduces a unified unitary and analytic model to accurately extract and compare the parameters of charged and neutral rho-meson families from diverse experimental data sets.

Findings

Precise neutral rho-meson parameters obtained.

Charged rho-meson parameters derived from weak pion form factor data.

Reliable differences between charged and neutral rho-meson parameters established.

Abstract

New very precise KLOE data on $\m{e}^+\m{e}^-\to\pi^+\pi^-$ obtained by radiative return method in Frascati are unified with corrected CMD-2 and SND Novosibirsk $\m{e}^+\m{e}^-\to\pi^+\pi^-$ data and supplemented below and beyond by older data in order to be described by the unitary and analytic pion electromagnetic form factor model, which provides the most precise neutral $\rho$-meson family parameters. Then the recently appeared accurate Belle (KEK) data of the weak pion form factor are described by the same unitary and analytic model, as it follows from the CVC hypothesis, providing the charged $\rho$-meson family parameters. As a result the most reliable parameter differences of the $\rho$-meson family are determined.