Measure of CP Nonconservation and Its Consequence on the Structure of the Kobayashi-Maskawa Matrix
Cherif Hamzaoui · Physical Review Letters · 1988
By use of unitarity of the Kobayashi-Maskawa matrix, the rephasing-invariant measure ${\ensuremath{\delta}}_{\mathrm{KM}}$ of $\mathrm{CP}$ nonconservation is evaluated in terms of the moduli squared of four matrix elements, which are taken as the four independent parameters. The striking feature of such a formulation is that the positivity of ${\ensuremath{\delta}}_{\mathrm{KM}}^{2}$ gives both upper and lower bounds on the matrix elements $|{V}_{\mathrm{cd}}|$, $|{V}_{\mathrm{cs}}|$, $|{V}_{\mathrm{td}}|$, and $|{V}_{\mathrm{ts}}|$.