Reactor neutrino oscillations as constraints on effective field theory

Abstract

We study constraints on the Standard Model Effective Field Theory (SMEFT) from neutrino oscillations in short-baseline reactor experiments. We calculate the survival probability of reactor antineutrinos at the leading order in the SMEFT expansion, that is including linear effects of dimension-6 operators. It is shown that, at this order, reactor experiments alone cannot probe charged-current contact interactions between leptons and quarks that are of the (pseudo)vector (V±A) or pseudo-scalar type. We also note that flavor-diagonal (pseudo)vector coefficients do not have observable effects in oscillation experiments. In this we reach novel or different conclusions than prior analyses of non-standard neutrino interactions. On the other hand, reactor experiments offer a unique opportunity to probe tensor and scalar SMEFT operators that are offdiagonal in the lepton-flavor space. We derive constraints on the corresponding SMEFT parameters using the most recent data from the Daya Bay and RENO experiments.

General neutrino interactions from an effective field theory perspective

“…Ideally, one would expect that the GNI Lagrangians (2), (3) emerge as the lowenergy limit of SMEFT. However, as pointed out in [13], both the GNI ansatz (or the general EFT below the weak scale therein referred to as "weak EFT"), and the SMEFT can be considered on an independent footing, which becomes relevant if there are new particles in the mass range of tens of GeV or if the electroweak symmetry is realised non-linearly in the new physics sector. In this work, however, we will assume that the low-energy theory can be matched to the high-energy EFT and discuss implications of this assumption.…”

“…There do exist, however, collider bounds on contact interactions, some of which we address for comparison. Here, we will not consider reactor neutrino oscillation experiments as another source of low-energy data, but refer to [13] for a recent analysis in the context of SMEFT.…”

Z′s in neutrino scattering at DUNE

“…Novel interactions in the neutrino sector have been proposed for a variety of reasons, including as a potentially observable effect in the neutrino oscillation probabilities (see, e.g., [30]), as a way of ameliorating tension introduced by sterile neutrinos in the early universe [31][32][33][34][35][36][37][38], and as a possible explanation of anomalous results at a short baseline [39][40][41]. Models that introduce new interactions between neutrinos and matter have been discussed in simplified settings [42][43][44], via effective field theory [45,46] and specific UV complete models [47] (see also [48] for a neutrinophilic Z 0 study at the DUNE ND). One class of models restricts the new interactions to leptons.…”

Probing new physics with long-range neutrino interactions: an effective field theory approach

“…As stated before, the commonly-studied SMEFT does not contain ν R and so can only produce a subset of the νLEFT operators containing just ν L . It may not even be possible to match these operators if there are new particles with masses O(100) GeV or if EW symmetry breaking is non-linear in the new physics sector [108]. Assuming that the matching is possible, in order to produce all low-energy operators, one can introduce n number of sterile states N R to the SMEFT.…”