In the analysis of epsilon'/epsilon it has been traditional to consider isospin breaking effects due to electroweak penguins and to pi⁰-eta and pi⁰-eta' mixing. We point out that there are other sources of isospin violation. In particular, we discuss isospin breaking effects affecting the matrix elements of the dominant gluonic penguin operators that are due to the non-zero light quark masses and find that they can be just as important.

Friday, April 28th 2000, 13:00
Ernest Rutherford Physics Building, room 326