a_1\pi Contribution to e^+e^-\to 4\pi Annihilation and \tau\to   4\pi\nu_{\tau} Decay
  The results of the study of the process e^+e^- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Simple model, based on the assumption of a_1(1260)\pi and \omega\pi dominance as intermediate states, successfully describes also the data of CLEOII and ALEPH obtained recently for the decay \tau\to 4\pi\nu_{\tau}. 
A.I. Milstein