Hierarchical structure of physical Yukawa couplings from matter field K\"ahler metric

Understand

We study the impacts of matter field K\"ahler metric on physical Yukawa couplings in string compactifications.

• Since the K\"ahler metric is non-trivial in general, the kinetic mixing of matter fields opens a new avenue for realizing a hierarchical structure of physical Yukawa couplings, even when holomorphic Yukawa couplings have the trivial structure.
• The hierarchical Yukawa couplings are demonstrated by couplings of pure untwisted modes on toroidal orbifolds and their resolutions in the context of heterotic string theory with standard embedding.
• Also, we study the hierarchical couplings among untwisted and twisted modes on resolved orbifolds.