Non-Standard Neutrino Interactions and Neutral Gauge Bosons

Abstract

We investigate Non-Standard Neutrino Interactions (NSI) arising from a flavor-sensitive $Z^{\prime }$ boson of a new $U(1{)}^{\prime }$ symmetry. We compare the limits from neutrino oscillations, coherent elastic neutrino-nucleus scattering, and $Z^{\prime }$ searches at different beam and collider experiments for a variety of straightforward anomaly-free $U(1{)}^{\prime }$ models generated by linear combinations of $B-L$ and lepton-family-number differences $L_{\alpha }-L_{\beta }$. Depending on the flavor structure of those models it is easily possible to avoid NSI signals in long-baseline neutrino oscillation experiments or change the relative importance of the various experimental searches. We also point out that kinetic $Z$-$Z^{\prime }$ mixing gives vanishing NSI in long-baseline experiments if a direct coupling between the $U(1{)}^{\prime }$ gauge boson and matter is absent. In contrast, $Z$-$Z^{\prime }$ mass mixing generates such NSI, which in turn means that there is a Higgs multiplet charged under both the Standard Model and the new $U(1{)}^{\prime }$ symmetry.

Comments: 25 pages; improved discussion of mass-mixing case; to appear in SciPost