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[Display omitted] QED atoms are composed of unstructured and point-like lepton pairs bound together by the electromagnetic force. The smallest and heaviest QED atom is formed by a τ + τ - pair. Currently, the only known atoms of this type are the e + e - and μ + e - atoms, which were discovered 64 years ago and remain the sole examples found thus far. We demonstrate that the J τ ( τ + τ - atom with J PC = 1 - - ) atom signal can be observed with a significance larger than 5 σ including both statistical and systematic uncertainties, via. the process e + e - → X + Y - Ɇ (X , Y = e , μ , π , K , or ρ , and Ɇ is the missing energy due to unobserved neutrinos) with 1.5 ab - 1 data taken around the τ pair production threshold. The τ lepton mass can be measured with a precision of 1 keV with the same data sample. This is within one year's running time of the proposed super tau-charm facility in China or super charm-tau factory in Russia. [ABSTRACT FROM AUTHOR]