Loop-generated neutrino masses in composite Higgs models

Abstract

We present a composite scotogenic model for neutrino masses, which are generated via loops of ℤ2-odd composite scalars. We consider three different approaches to the couplings of the neutrinos (including three right-handed singlets) and the composite sector: ETC-like four-fermion interactions, fundamental partial compositeness and fermion partial compositeness. In all cases, the model can feature sizeable couplings and remain viable with respect to various experimental constraints if the three ℤ2-odd right-handed neutrinos have masses between the TeV and the Planck scales. Additionally, the lightest ℤ2-odd composite scalar may play the role of Dark Matter, either via thermal freeze-out or as an asymmetric relic. This mechanism can be featured in a variety of models based on vacuum misalignment. For concreteness, we demonstrate it in a composite two-Higgs scheme based on the coset SU(6)/Sp(6).

Bridging the μHz gap in the gravitational-wave landscape: unveiling dark baryons

“…Finally, there is compelling motivation to suggest that both VM and DM asymmetries are generated through leptogenesis at a scale of approximately 1 − 10 TeV, such as resonant leptogenesis [28][29][30] and thermal leptogenesis in E. Ma's scotogenic model of radiative neutrino masses [31,32] or other radiative neutrino JHEP05(2024)193 mass models [32]. Interestingly, radiative neutrino mass generation can be realized with composite Higgses [64,65]. These models provide masses of the new states to be around O(1 − 10) TeV, making them testable in future colliders.…”

“…Finally, due to the fact that we have motivated a new physics scale at approximately O(1 − 10) TeV, low-scale alternatives to standard thermal leptogenesis are very motivated, such as resonant leptogenesis [28][29][30] and thermal leptogenesis in E. Ma's scotogenic model of radiative neutrino masses [31,32] or other radiative neutrino mass models [32]. Interestingly, radiative neutrino mass generation can be realized with composite Higgses [64,65]. These alternatives allow for masses of the new states to be around O(1 − 10) TeV.…”

The decomposition of neutron-antineutron oscillation operators

“…In this section, we will give an example of realizing the tiny neutrino mass and n − n oscillation simultaneously via a one-loop model. We focus on the Scotogenic-type neutrino mass model, which has been widely discussed, see for instance [32][33][34][35][36][37][38][39][40][41][42][43][44]. In addition, we consider the one-loop neutron-antineutron diagram T-L-8.…”

Charged lepton flavor violating processes in the Grimus-Neufeld model

“…[22,23]). These mass mechanisms can be embedded into more exotic models, for example, the seesaw mechanism can arise from extra dimensions [24,25], or radiative neutrino generation can be realized with composite Higgses [26,27]. While virtually all scenarios can fit the current experimental constraints, it is far harder to claim the strictly excluded regions unambiguously, especially when one studies more general scenarios with an overwhelming number of free parameters (see e.g.…”