Figure 1: Typical hadronic spectral function, , at , curve (a), showing a pole and three resonances. The squared-energy is the threshold for PQCD. At finite , curve (b), the stable hadron develops a width, the resonances become broader (only one survives in this example), and the PQCD threshold, , approaches the origin. Eventually, at , there will be no trace of resonances, and . |