# Contents

## Idea

In the standard model of particle physics, the Yukawa couplings encode the interaction between the fundamental fermion fields and the Higgs field, and thus, via the Higgs mechanism, the masses of the fermion field after electroweak symmetry breaking.

## In string phenomenology

In intersecting D-brane models Yukawa couplings are encoded by worldsheet instantons of open strings stretching between the intersecting D-branes (see Marchesano 03, Section 7.5). Mathematically this is encoded by derived hom-spaces in a Fukaya category (see Marchesano 03, Section 7.5).

table grabbed from Marchesano 03

## References

### General

Realistic Yukawa couplings and fermion masses in an MSSM Pati-Salam GUT model with 3 generations of fermions realized on intersecting D6-branes KK-compactified on a toroidal orbifold $T^6\sslash (\mathbb{Z}_2 \times \mathbb{Z}_2)$ are claimed in