Flavor Physics and CP from Non-Invertible Selection Rules

by Prof. Hajime Otsuka (Kyushu University)

Monday 26 Jan 2026, 15:00 → 16:00 Asia/Shanghai

Tsung-Dao Lee Institute/N6F-N600 - Lecture Room (Tsung-Dao Lee Institute)

Abstract:

In this talk, I will discuss the application of non-invertible selection rules to flavor physics and CP symmetry, in which matter fields are labeled by conjugacy classes of a finite group rather than its irreducible representations. We show that this framework leads to novel texture structures in the Yukawa couplings of quarks and leptons that cannot be realized by conventional group-theoretic (invertible) symmetries. Furthermore, when the fusion rules admit a Z2 symmetry identified with charge conjugation, a CP-invariant system can be consistently defined together with parity transformation. As a result, combining group-based flavor symmetries underlying non-invertible selection rules with CP symmetry naturally gives rise to a generalized CP transformation. We also demonstrate the possibility of spontaneous CP violation in this framework and discuss its implications for Yukawa textures. Finally, I will introduce top-down realizations of non-invertible selection rules arising from string compactifications, such as type IIB superstring theory on toroidal orbifolds and heterotic string theory on non-Abelian orbifolds.

Online Meeting Room: https://meeting.tencent.com/dm/v2K9WOG6OA3c

ID: 866987061