Neutrino nonstandard interactions with arbitrary couplings to u and d quarks

We introduce a model for nonstandard neutral current interaction (NSI) between neutrinos and the matter fields, with an arbitrary coupling to the up and down quarks. The model is based on a new U(1) gauge symmetry with a light gauge boson that mixes with the photon. We show that the couplings to the u and d quarks can have a ratio such that the contribution from NSI to the coherent elastic neutrino-nucleus scattering (CE nu NS) amplitude vanishes, relaxing the bound on the NSI from the CE nu NS experiments. Additionally, the deviation of the measured value of the anomalous magnetic dipole moment of the muon from the standard-model prediction can be fitted. The most limiting constraints on our model come from the search for the decay of the new gauge boson to e-e+ and invisible particles, carried out by NA48/2 and NA64, respectively. We show that these bounds can be relaxed by opening up the decay of the new gauge boson to new light scalars that eventually decay into the e-e+ pairs. We show that there are ranges that can lead to both a solution to the (g - 2)mu anomaly and values of epsilon mu mu = epsilon tau tau large enough to be probed by future solar neutrino experiments.

Automated summary

We propose a model for nonstandard neutral current interaction (NSI) between neutrinos and matter fields, with arbitrary couplings to up and down quarks. Our model is based on a new U(1) gauge symmetry with a light gauge boson that mixes with the photon. We show that the couplings to the quarks can be adjusted to eliminate the contribution from NSI to coherent elastic neutrino-nucleus scattering, and can also account for the discrepancy in the muon's anomalous magnetic dipole moment.