Abstract
We confront the new physics models with extra isosinglet down quarks in the new violation experimental era with and measurements, events, and limits. The closeness of the new experimental results to the standard model theory requires us to include full standard model (SM) amplitudes in the analysis. In models allowing mixing to a new isosinglet down quark, as in flavor changing neutral currents are induced that allow a mediated contribution to mixing and which bring in new phases. In and plots we still find much larger regions in the four down quark model than in the SM, reaching down to and down to zero, all at We elucidate the nature of the cancellation in an order four down quark mixing matrix element which satisfies the experiments and reduces the number of independent angles and phases. We also evaluate tests of unitarity for the Cabibbo-Kobayashi-Maskawa submatrix.
- Received 1 May 2002
DOI:https://doi.org/10.1103/PhysRevD.66.016008
©2002 American Physical Society