# The Two Higgs-Doublet Extension of the Standard Model and S3 Symmetry

## TL;DR

This paper introduces a two Higgs-doublet extension of the Standard Model with S3 symmetry, predicting the top quark mass and naturally eliminating flavor-changing neutral currents.

## Contribution

It presents a novel S3 symmetric two Higgs-doublet model that predicts the top quark mass and ensures the absence of flavor-changing neutral currents.

## Key findings

- Predicts top quark mass as 39 GeV at 1 GeV scale
- Flavor changing neutral currents vanish automatically
- Provides a mass relation from symmetry breaking

## Abstract

(This is a recompiled version of $Chin. J. of Phys., Vol. 26, No. 4, 180$ since the previous available electronic document on web was unreadable) We impose a permutation symmetry S3 upon the two Higgs doublet extension of the SU(2) x U( 1) standard model, and then break S3 symmetry spontaneously. A mass relation is obtained from which the mass of the top quark is predicted to be 39 Gev at 1 Gev renormalization scale, if the relative strength between the coupling of the first Higgs field with the up-type quarks is assumed to be the same as that with the down-type quarks. We find that in our model the flavor changing neutral currents vanish automatically.