Radiative generation of quark masses and mixing angles in the two Higgs doublet model

Alejandro Ibarra,Ana Solaguren-Beascoa

doi:10.1016/j.physletb.2014.06.071

Alejandro Ibarra, Ana Solaguren-Beascoa

Open Access

https://doi.org/10.1016/j.physletb.2014.06.071

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Abstract

We present a framework to generate the quark mass hierarchies and mixing angles by extending the Standard Model with one extra Higgs doublet. The charm and strange quark masses are generated by small quantum effects, thus explaining the hierarchy between the second and third generation quark masses. All the mixing angles are also generated by small quantum effects: the Cabibbo angle is generated at zeroth order in perturbation theory, while the remaining off-diagonal entries of the Cabibbo–Kobayashi–Maskawa matrix are generated at first order, hence explaining the observed hierarchy |Vub|,|Vcb|≪|Vus|. The values of the radiatively generated parameters depend only logarithmically on the heavy Higgs mass, therefore this framework can be reconciled with the stringent limits on flavor violation by postulating a sufficiently large new physics scale.

Highlights

The quark masses and mixing angles are fundamental parameters in the Standard Model of Particle Physics which must be determined experimentally
The charm and strange quark masses are generated by small quantum effects, explaining the hierarchy between the second and third generation quark masses
A very popular approach consists in postulating the existence of a “horizontal” U(1) symmetry, under which the left- and righthanded quarks of different generations transform differently, and which is assumed to be spontaneously broken at an energy below a certain cut-off

Summary

Introduction

The quark masses and mixing angles are fundamental parameters in the Standard Model of Particle Physics which must be determined experimentally. The masses and mixing angles arise as powers of the small ratio of the U(1) symmetry breaking scale over the cut-off scale [1]. This approach has been generalized to non-Abelian symmetries, e.g in [2, 3] or to discrete symmetries, e.g in [4]. In this letter we will present a mechanism to generate quark mass hierarchies and mixing angles in the framework of the general two Higgs doublet model. We will show that in this scheme the radiatively generated quark masses are only mildly dependent on the scale of new physics and the same conclusions remain valid even in the decoupling limit

Flavor structures in the 2HDM

Quantum effects on the quark masses and mixing angles

Conclusions

A Appendix: beta functions