New Physics and Evidence for a Complex CKM

Abstract

We carefully analyse the present experimental evidence for a complex CKM matrix, even allowing for New Physics contributions to $ε_{K}$, $a_{J/ΨK_S}$, $ΔM_{B_{d}}$, $ΔM_{B_{s}}$, and the $ΔI=1/2$ piece of $B\toρρ$ and $B\toρπ$. We emphasize the crucial r\^ ole played by the angle $γ$ in both providing irrefutable evidence for a complex CKM matrix and placing constraints on the size of NP contributions. It is shown that even if one allows for New Physics a real CKM matrix is excluded at a 99.92% C.L., and the probability for the phase $γ$ to be in the interval $[-170^\circ;-10^\circ]\cup [10^\circ;170^\circ]$ is 99.7%.

24 pages, 15 figures. Revised version, analyses extended to more general New Physics; C.L. of exclusion of a real CKM matrix included