Constraints on the X17 boson from IceCube searches for non-standard interactions of neutrinos

Abstract

We explain the ATOMKI anomaly with a very light Z ' state that features non-anomalous and non-flavour-universal vector and axial-vector couplings to all leptons. This Z ' comes from a theoretical framework with a spontaneously broken U(1)' symmetry in addition to the Standard Model gauge group and is compliant with current measurements of the anomalous magnetic moments of the electron and the muon as well as beam dump experiments. The lepton flavour structure of this model allows for Z ' couplings to all light neutrinos, suggesting the possibility of Z '-mediated Non-Standard Interactions (NSIs) of neutrinos in matter, so that measurements of the strength parameters of the NSIs can constrain the value of the couplings. We use experimental constraints on NSIs of neutrinos using older TEXONO data and newer IceCube data. The IceCube data, in particular, strongly constrain the flavour universality of the leptonic vector current. The constraints enable us to define the region of parameter space of this theoretical scenario that can be pursued in further phenomenological analyses.