A three-loop radiative neutrino mass model with dark matter

Abstract

We present a model that generates small neutrino masses at three-loop level due to the existence of Majorana fermionic dark matter, which is stabilized by a Z 2 symmetry. The model predicts that the lightest neutrino is massless. We show a prototypical parameter choice allowed by relevant experimental data, which favors the case of normal neutrino mass spectrum and the dark matter with m ∼ 50-135 GeV and a sizable Yukawa coupling. It means that new particles can be searched for in future e + e − collisions.

ScotogenicRνMDMat three-loop level

“…A common feature of the models in [16,17] are super-renormalizable terms violating a desired Z 2 symmetry. In our case such unique term (14) is forbidden by exact Z 2 symmetry originating in the 2HD sector in our setup. The Z 2 charges have to be attributed also to exotic sector states as displayed in Table 1, in order to enable the neutrino mass loop diagram.…”

“…However, it is known that soft breaking of Z 2 in 2HDM may have some interesting features, like introducing a new source of CP violation and preserving stability and unitarity of the scalar potential. In the 2HD sector there is a potential soft m 12 term (5), whereas the Z 2 -breaking soft term (14) in the sector of exotic scalar fields 4 Neutral current partonic production processes are enhanced by electric charge factors (thanks to the hypercharge being zero) like Q ( ++ ) 2 + Q ( + ) 2 = 2 2 + 1 2 = 5, while the corresponding charged current partonic production processes are enhanced by electroweak SU(2) ladder operators matrix elements Let us for completeness estimate the value of the small, 'tHooftnatural coefficient carried by the term (14), so that the loopinduced decays of 0 state may be long enough in comparison to the lifetime of the Universe.…”

“…Also, an antisymmetric tensor field may be stable [7] without introducing a new Z 2 symmetry. for a charged scalar singlet in the KNT model [14]. The KNT model has been partly self-criticized [15] because of employing unobservable singlet DM.…”

Connecting neutrino masses and dark matter by high-dimensional lepton number violation operator

“…Such a connection has been already exemplified by some recent three-loop neutrino mass models [13,[39][40][41], which realize the dimension-9 effective operator…”

Comment on “A three-loop radiative neutrino mass model with dark matter” [Phys. Lett. B 741 (2015) 163]

“…It is more intriguing that these two physics have a common origin. Jin, Tang and Zhang [1] proposed an interesting model which generates neutrino masses at three-loop level, trying to explicitly provide such a connection. However, in the original estimation of neutrino masses, some important contributions, i.e.…”