Abstract

Motivated by models for neutrino masses and lepton mixing, we consider the renormalization of the lepton sector of a general multi-Higgs-doublet Standard Model with an arbitrary number of right-handed neutrino singlets. We propose to make the theory finite by overline{mathrm{MS}} renormalization of the parameters of the unbroken theory. However, using a general Rξ gauge, in the explicit one-loop computations of one-point and two-point functions it becomes clear that — in addition — a renormalization of the vacuum expectation values (VEVs) is necessary. Moreover, in order to ensure vanishing one-point functions of the physical scalar mass eigenfields, finite shifts of the tree-level VEVs, induced by the finite parts of the tadpole diagrams, are required. As a consequence of our renormalization scheme, physical masses are functions of the renormalized parameters and VEVs and thus derived quantities. Applying our scheme to one-loop corrections of lepton masses, we perform a thorough discussion of finiteness and ξ-independence. In the latter context, the tadpole contributions figure prominently.

Highlights

  • In this paper we propose a renormalization scheme for the multi-Higgs-doublet Standard Model

  • Extensions of the scalar sector play an important role in lepton mass and mixing models

  • In this paper we have considered an important class of such models, the multi-Higgs-doublet Standard Model (mHDSM), which has an arbitrary number nH of Higgs doublets and an arbitrary number nR of right-handed neutrino singlets with Majorana mass terms

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Summary

Introduction

In this paper we propose a renormalization scheme for the multi-Higgs-doublet Standard Model (mHDSM). Having obtained δ∆k, δΓk, δvk and the counterterm of the scalar one-point function, all ingredients required for the counterterms of the fermion self-energies are at hand and can be determined We demonstrate that these make the neutrino selfenergy Σν and the charged-lepton self-energy Σl finite.. In an n-point function with n ≥ 2 one can either take into account these VEV shifts or, equivalently, include all tadpole diagrams instead, as shown for the SM in [22, 23] We show this explicitly in the mHDSM at the one-loop level for the neutrino and charged-lepton self-energies. In appendix D we convert the loop functions that we use in section 6 to other functions commonly used in the literature

Yukawa Lagrangian and lepton mass matrices
Vector boson-scalar interactions
Triple scalar interactions
Scale factors in dimensional regularization
The counterterms for the one- and two-point scalar functions
Renormalization of the quartic scalar couplings
Divergencies of the neutral-scalar self-energy
Finiteness of the scalar one-point function
Two decompositions of the fermion self-energy
Gauge-parameter cancellation in fermion self-energy loops
Yukawa coupling renormalization and mass counterterms
Finiteness of the fermion self-energies
Neutrinos
Charged leptons
One-loop fermion self-energy formulas in Feynman gauge
Self-energies
Seesaw mechanism
Conclusions
A The scalar mass matrices
B The diagonalization matrices of the charged and neutral scalar mass terms
C On-shell contributions to the fermion self-energies
D Conversion to scalar Feynman integrals
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