Study of the Process $e^+e^-\to Ï^+Ï^-Ï^+Ï^-$ IN THE C.M. Energy Range 920--1060 MeV with the CMD-3 Detector
arXiv:1612.04483 · doi:10.1016/j.physletb.2017.03.022
Abstract
A cross section of the process $e^+e^- \to \pipi\pipi$ has been measured using 6798$\pm$93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pb$^{-1}$ collected with the CMD-3 detector in the center-of-mass energy range 920--1060 MeV. The measured cross section exhibits an interference pattern of the $Ï(1020)\to\pipi\pipi$ decay with a non-resonant process $e^+e^- \to \pipi\pipi$, from which we obtain the branching fraction of the doubly suppressed decays (by G-parity and OZI rule): $\BR(Ï\to\pipi\pipi) = (6.5\pm2.7\pm1.6)\times 10^{-6}$.
16 pages, 6 figures