Feasibility to probe the dynamical scotogenic model at the LHC

TL;DR

This work assesses the collider feasibility of the dynamical scotogenic model, which links neutrino masses and dark matter through a global U(1)$_L$ symmetry and a Z$_2$-odd dark sector. By performing an MCMC scan that honors neutrino data, Higgs invisible decays, and DM constraints, the authors identify viable compressed-spectrum regions and evaluate Drell–Yan and Vector Boson Fusion production at the LHC. They find that fermionic DM can be probed via DY at the HL-LHC for masses between 100 and 220 GeV, while VBF channels remain below reach for both DM candidates; scalar DM prospects are generally poor at the LHC but may benefit modestly from FCC-hh energies. Overall, the DY channel provides the best collider sensitivity to fermionic DM in this framework, with future higher-energy machines offering incremental gains in specific mass ranges.

Abstract

We perform a feasibility study to probe dark matter (DM) production at the LHC within a global $U(1)_L$ scotogenic model. The study is conducted using the Markov Chain Monte Carlo numerical method, considering the viable parameter space of the model allowed by experimental constraints such as neutrino oscillation data, the Higgs to invisible branching fraction, and DM observables. The production of scalar and fermionic DM candidates, predicted by the model, is then studied under the LHC conditions for different luminosity scenarios imposing compressed mass spectra conditions between the lightest fermion and the $\mathbb{Z}_2$ odd scalars. We studied two production mechanisms, Drell-Yan and Vector Boson Fusion. It was found that the Drell-Yan mechanism gives better detection prospects for fermionic DM masses between 100-220~\textrm{GeV} at high luminosity scenarios.

Figures (9)

• Figure 1: Representative Feynman diagram illustrating the generation of the neutrino mass matrix element $~(M_{\nu})_{ij}~$ in the physical basis. The $\eta^0$ state represents both the neutral scalar $\eta_R$ and the pseudo-scalar $\eta_I$, while $N$ denotes any of the three new Majorana fermions running in the loop.
• Figure 2: Feynman diagrams associated with the production of DM via DY processes at the LHC. Left: sample topology for the production of the scalar DM candidate, $\eta_I$, along with a Majorana fermion and SM particles as final states. Right: sample topology for the production of the fermionic DM candidate, $N_1$, along with two SM leptons.
• Figure 3: Feynman diagrams illustrating the production of DM via VBF processes. The scalar DM channel is depicted on the left, while the fermionic channel is shown on the right.
• Figure 4: Relative contribution of each processes to the relic density projected on the DM mass when $N_1$ is the DM candidate and for $m_{h_2}=246\,\textrm{GeV}$ and $\Delta m < 30~\textrm{GeV}$.
• Figure 5: Relative contribution of each processes to the relic density projected on the DM mass when $\eta_I$ is the DM candidate and for $m_{h_2}=246\,\textrm{GeV}$ and $\Delta m < 30~\textrm{GeV}$.