Dirac neutrinos from Peccei-Quinn symmetry: Two examples

The Scotogenic model is an economical setup that induces Majorana neutrino masses at the 1-loop level and includes a dark matter candidate. We discuss a generalization of the original Scotogenic model with arbitrary numbers of generations of singlet fermion and inert doublet scalar fields. First, the full form of the light neutrino mass matrix is presented, with some comments on its derivation and with special attention to some particular cases. The behavior of the theory at high energies is explored by solving the Renormalization Group Equations.

Section: Jhep07(2020)097mentioning

confidence: 99%

Generalizing the Scotogenic model

Escribano

Reig

Vicente

2020

“…Moreover, in recent times the topic of Dirac neutrino masses is getting more and more attention [100][101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116], fueled by the as of yet non-observation of neutrinoless double beta decay. It has also been shown that the PQ symmetry can protect the Dirac nature of neutrinos [117][118][119]. Therefore, let us briefly expose how one could extend this mechanism to neutrinos too.…”

Section: Jhep09(2020)137 B Dirac Neutrinos From Pq Symmetrymentioning

confidence: 99%

Natural axion model from flavour

Chuliá

Döring

Rodejohann

et al. 2020

We explore a common symmetrical origin for two long standing problems in particle physics: the strong CP and the fermion mass hierarchy problems. The Peccei-Quinn mechanism solves the former one with an anomalous global U(1)PQ symmetry. Here we investigate how this U(1)PQ could at the same time explain the fermion mass hierarchy. We work in the context of a four-Higgs-doublet model which explains all quark and charged fermion masses with natural, i.e. order 1, Yukawa couplings. Moreover, the axion of the model constitutes a viable dark matter candidate and neutrino masses are incorporated via the standard type-I seesaw mechanism. A simple extension of the model allows for Dirac neutrinos.

“…GeV. Other studies on the link between U(1) PQ symmetry and neutrino/flavour can be found in [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63].…”

Section: The Axion and The Dirac Neutrinomentioning

confidence: 99%

A connection between flavour anomaly, neutrino mass, and axion

Baek

2020

We propose a minimal model in which the flavour anomaly in the b → sμ+μ− transition is connected to the breaking of Peccei-Quinn (PQ) symmetry. The flavour anomaly is explained from new physics contribution by introducing one generation of heavy quark and heavy lepton which are vector-like under the standard model (SM) gauge group but charged under a local U(1)X group. They mix with the SM quarks and leptons, inducing flavour-changing Z′ couplings, which generates the b → sμ+μ− anomaly at tree level. On the other hand the new fermions are chiral under the global Peccei-Quinn(PQ) symmetry. The pseudo-Goldstone boson coming from the spontaneous breaking of the PQ symmetry becomes an axion, solving the strong CP problem and providing a cold dark matter candidate. The same symmetry prevents the right-handed neutrino from having a Majorana mass term. But the introduction of a neutrino-specific Higgs doublet allows neutrino to have Dirac mass term without fine-tuning problem. The model shows an interplay between axion, neutrino, dark matter, and flavour physics.