Abstract
Radiatively generated neutrino masses ($m_\nu$) are proportional to supersymmetry (SUSY) breaking, as a result of the SUSY non-renormalisation theorem. In this work, we investigate the space of SUSY radiative seesaw models with regard to their dependence on SUSY breaking ($\require{cancel}\cancel{\text{SUSY}}$). In addition to contributions from sources of $\cancel{\text{SUSY}}$ that are involved in electroweak symmetry breaking ($\cancel{\text{SUSY}}_\text{EWSB}$ contributions), and which are manifest from $\langle F^\dagger_H \rangle = \mu \langle \bar H \rangle \neq 0$ and $\langle D \rangle = g \sum_H \langle H^\dagger \otimes_H H \rangle \neq 0$, radiatively generated $m_\nu$ can also receive contributions from $\cancel{\text{SUSY}}$ sources that are unrelated to EWSB ($\cancel{\text{SUSY}}_\text{EWS}$ contributions). We point out that recent literature overlooks pure-$\cancel{\text{SUSY}}_\text{EWSB}$ contributions ($\propto \mu / M$) that can arise at the same order of perturbation theory as the leading order contribution from $\cancel{\text{SUSY}}_\text{EWS}$. We show that there exist realistic radiative seesaw models in which the leading order contribution to $m_\nu$ is proportional to $\cancel{\text{SUSY}}_\text{EWS}$. To our knowledge no model with such a feature exists in the literature. We give a complete description of the simplest model-topologies and their leading dependence on $\cancel{\text{SUSY}}$. We show that in one-loop realisations $L L H H$ operators are suppressed by at least $\mu \, m_\text{soft} / M^3$ or $m_\text{soft}^2 / M^3$. We construct a model example based on a one-loop type-II seesaw. An interesting aspect of these models lies in the fact that the scale of soft-$\cancel{\text{SUSY}}$ effects generating the leading order $m_\nu$ can be quite small without conflicting with lower limits on the mass of new particles.
Highlights
The large hierarchy between neutrino masses and the electroweak (EW) scale may be regarded a symptom of an hierarchy between the latter and a new mass scale (M) that holds lepton number (L-number) breaking
While the smallness of mν points towards an high seesaw scale M, the resolution of the hierarchy problem suggests that the scale of soft-SUSY should lie close to the TeV scale
By classifying the dependence on SUSY according to their involvement in EWSB, we identified a subset of model topologies in which the leading contributions to m on SUSY sources that are not involved in EWSB
Summary
The large hierarchy between neutrino masses (mν) and the electroweak (EW) scale may be regarded a symptom of an hierarchy between the latter and a new mass scale (M) that holds lepton number (L-number) breaking. If L L H H is radiatively generated [23,24,25,26], loop factors and many coupling dependence may help bringing M close to the TeV scale. This possibility arises naturally in models in which the sector holding L-number breaking is charged under a symmetry with respect to (w.r.t.) which L and H are neutral. Such a symmetry may find its motivation connected to the stability of dark matter, as discussed
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.