Flavor physics beyond the Standard Model and the Kobayashi-Maskawa legacy

Abstract

The Kobayashi-Maskawa (KM) hypothesis about the existence of a third generation of quarks represents a cornerstone of the Standard Model (SM). Fifty years after this seminal paper, flavor physics continues to represent a privileged observatory on physics occurring at high energy scales. In this paper I first review this statement using general effective-theory arguments, highlighting some interesting modern lessons from the KM paper. I then discuss some novel extensions of the SM based on the concept of flavor deconstruction: the hypothesis that gauge interactions are manifestly flavor non universal in the ultraviolet. The phenomenological consequences of this class of models are also briefly illustrated.

arXiv comment17 pages, based on the talk given at the KM50 Symposium (KEK, February 2023)