B Factory Constraints on Isosinglet Down Quark Mixing, and Predictions For Other CP Violating Experiments

Abstract

In the main part of the paper we project forward to having $B$ factory determinations of $\sin(2β)$ and $\sin(2α)$, for which we take several values. First, we use a joint $χ^2$ analysis of CKM experiments to constrain CKM matrix elements in the standard model, and experiments on the angles $α$, $β$, and $γ$, and on $x_s$ and null $CP$ asymmetries. Then we invoke mixing to a new isosinglet down quark (as in E$_6$) which induces FCNC that allow a $Z^0$ mediated contribution to $B-\bar B$ mixing and which brings in new phases. We then repeat the $χ^2$ analysis, now including experimental constraints from FCNC as well, finding much larger ranges of prediction for the $B$ factory. We then add projected $B$ factory results on $\sin(2β)$ and $\sin(2α)$ and repeat both analyses. In $(ρ,η)$ and $(x_s,\sin{(γ)})$ plots for the extra isosinglet down quark model, we find multiple regions that will require experiments on $\sin{(γ)}$ and/or $x_s$ to decide between and possibly to effectively bound out the extra down quark contribution.