TAU-]PI-K-NU DECAY AND PI-K SCATTERING

Using chiral low energy theorems and elastic unitarity assumption, the tau --> pi K nu decay is investigated. The vector and scalar pi K for m factors are calculated. It is found that the pi K spectrum is domina ted by the K resonance, By measuring the forward-backward asymmetry, it is shown that the S wave pi K phase shift can be determined near th e K resonance region. The calculated branching ratio and resonance pa rameters are in good agreement with experiments.