The Physics and Prospects of Super Tau–Charm Factories

Abstract

The proposed super tau–charm factories are a powerful new class of high-luminosity electron–positron colliders operating in the center-of-mass energy range between 2 and 7 GeV, a region that spans thresholds for tau leptons, open-charm hadrons, charmonium and charmonium-like states, hyperons, and light hadrons. With unprecedented data samples, threshold kinematics, and quantum-coherent production, these facilities offer unique opportunities to advance precision tests of the Standard Model and to search for physics beyond it. In this review, we examine the physics prospects of the Super Tau–Charm Facility, focusing on precision charm measurements, CP violation in mesons and baryons, tau-lepton properties and rare decays, and nonperturbative QCD phenomena such as hadronization, spectroscopy, and time-like form factors. We also discuss the experimental landscape, technological challenges, and complementarity with existing and planned facilities. Together, these capabilities position super tau–charm factories at the forefront of the precision frontier in particle physics.