Measurement of $e^{+}{e}^{-}\to \omega {\pi }^{+}{\pi }^{-}$ cross section at $\sqrt{s}=$ 2.000 to 3.080 GeV

Abstract

A partial wave analysis on the process $e^{+}{e}^{-}\to \omega {\pi }^{+}{\pi }^{-}$ is performed using 647 pb${}^{-1}$ of data sample collected by using the BESIII detector operating at the BEPCII storage ring at center-of-mass (c.m.) energies from 2.000 GeV to 3.080 GeV. The Born cross section of the $e^{+}{e}^{-}\to \omega {\pi }^{+}{\pi }^{-}$ process is measured, with precision improved by a factor of 3 compared to that of previous studies. A structure near 2.25 GeV is observed in the energy-dependent cross sections of $e^{+}{e}^{-}\to \omega {\pi }^{+}{\pi }^{-}$ and $\omega {\pi }^0{\pi }^0$ with a statistical significance of 7.6$\sigma$, and its determined mass and width are 2232 $\pm$ 19 $\pm$ 27 MeV$/c^2$ and 93 $\pm$ 53 $\pm$ 20 MeV, respectively, where the first and second uncertainties are statistical and systematic, respectively. By analyzing the cross sections of subprocesses $e^{+}{e}^{-}\to \omega f_0(500)$, $\omega f_0(980)$, $\omega f_0(1370)$, $\omega f_2(1270)$, and $b_1(1235)\pi$, a structure, with mass M = 2200 $\pm$ 11 $\pm$ 17 MeV/$c^2$ and width $\Gamma$ = 74 $\pm$ 20 $\pm$ 24 MeV, is observed with a combined statistical significance of 7.9$\sigma$. The measured resonance parameters will help to reveal the nature of vector states around 2.25 GeV.

arXiv comment34 pages,13 figures