Hunting the elusive $\textit{X}$17 in CE$\textit{ν}$NS at the ESS

The so-called $\textit{X}$17 particle has been proposed in order to explain a very significant resonant behaviour (in both the angular separation and invariant mass) of $\textit{e}$ $\textit{e}$ pairs produced during a nuclear transition of excited Be, He and C nuclei. Fits to the corresponding data point, as most probable explanation, to a spin-1 object, which is protophobic and has a mass of approximately 16.7 MeV, which then makes the $\textit{X}$17 potentially observable in Coherent Elastic neutrino ($\textit{ν}$) Nucleus Scattering (CE$\textit{ν}$NS) at the European Spallation Source (ESS). By adopting as theoretical framework a minimal extension of the Standard Model (SM) with a generic U(1)$\textit{′}$ gauge group mixing with the hypercharge one of the latter, which can naturally accommodate the $\textit{X}$17 state compliant with all available measurements from a variety of experiments, we predict that CE$\textit{ν}$NS at the ESS will constitute an effective means to probe this hypothesis, even after allowing for the inevitable systematics associated to the performance of the planned detectors therein.