We propose our framework as an effective field theory valid below the cutoff scale $\mathrm{\Lambda }$, in which we explain the tiny scale of neutrino masses by integrating a noninvertible symmetry with the dynamical determination of the cutoff scale. In our model, we introduce three families of ${\mathrm{SU}(2)}_L$ quintet fermions (${\mathrm{\Sigma }}_R$) and a quartet scalar (${\varphi }_4$), both of which are charged under the Fibonacci fusion rule (FFR). A central feature of this construction is that the vacuum expectation value (VEV) $v_4$ of ${\varphi }_4$ is induced at the one-loop level via dynamical symmetry breaking. To resolve the inherent arbitrariness of the cutoff scale $\mathrm{\Lambda }$ in loop-induced VEV models, we identify $\mathrm{\Lambda }$ with the scale at which the $SU(2{)}_L$ gauge coupling $g_2$ encounters the renormalization group evolution (RGE) of $g_2$, naturally fixing the physical cutoff within the range of approximately ${10}^5$ to ${10}^7\mathrm{GeV}$. Quantitatively, this framework yields $v_4\sim 0.07–0.1\mathrm{GeV}$, which in turn leads to neutrino Yukawa couplings on the order of ${10}^{-3}$. This result provides a significantly more natural explanation for the neutrino mass hierarchy compared to standard seesaw models, which typically require couplings as small as ${10}^{-6}$ or less. Notably, our approach maintains a relatively simple particle content and does not necessitate additional (gauge) bosons for symmetry breaking.

Close

PrevNext

Reuse & PermissionsView figure in article

• 
• 

• Extensions of fermion sector
• Extensions of scalar sector
• Hierarchy problem
• Neutrinos