I analyze D-D mixing using the techniques of heavy quark effect field theory. [1] The analysis suggests that the there may be important cancellations among the dispersive effects of different kinds of final states, so that the total mixing may be considerably smaller than previous estimates. [2, 3]

Using the natural differential dispersive character of the renormalization group, we give a possible explanation of the present high energy data for e+ehadrons. *Work supported in part by the U.S. Atomic Energy Commission.

v 1 INTRODUCTION 1

We present a new dispersive analysis of the isospin breaking decay η → 3π. The resulting representation of the decay amplitude allows us to determine the quark mass double ratio Q and we find as a preliminary result Q = 22.3 ± 0.4. Finally, we discuss a number of improvements that we intend to implement in the future.