Nicola Cabibbo (1935–2010)

Nicola Cabibbo organized decay probability amplitudes of the weak interaction through a single mixing angle. His 1963 paper related strangeness-conserving and strangeness-changing processes within a symmetry-based weak current. In modern quark notation, the combination $d^{\prime }=d\cos {\theta }_C+s\sin {\theta }_C$ expresses this quark mixing: the relative strengths depend on one Cabibbo angle. Comparing different decay rates therefore tests one common structure instead of fitting every weak channel independently. The quark notation is a later interpretation of the original current construction.^[ref]

A physicist working on quark mixing.^[ref]