Non-standard interactions in SMEFT confronted with terrestrial neutrino experiments

TL;DR

This paper explores how current neutrino oscillation experiments constrain non-standard interactions within the SMEFT framework, revealing significant sensitivity to new physics at high energy scales and emphasizing the complementarity of different experimental approaches.

Contribution

It provides a comprehensive analysis of neutrino NSIs in SMEFT, including matching, renormalization group running, and the impact of multiple operators, with novel constraints surpassing collider bounds.

Findings

Neutrino experiments can probe new physics at ~20 TeV scale.

Constraints vary significantly when multiple operators are considered.

Accelerator and reactor experiments target different SMEFT operators.

Abstract

The Standard Model Effective Field Theory (SMEFT) provides a systematic and model-independent framework to study neutrino non-standard interactions (NSIs). We study the constraining power of the on-going neutrino oscillation experiments T2K, NO$\nu$A, Daya Bay, Double Chooz and RENO in the SMEFT framework. A full consideration of matching is provided between different effective field theories and the renormalization group running at different scales, filling the gap between the low-energy neutrino oscillation experiments and SMEFT at the UV scale. We first illustrate our method with a top-down approach in a simplified scalar leptoquark model, showing more stringent constraints from the neutrino oscillation experiments compared to collider studies. We then provide a bottom-up study on individual dimension-6 SMEFT operators and find NSIs in neutrino experiments already sensitive to new physics at $\sim$20 TeV when the Wilson coefficients are fixed at unity. We also investigate the correlation among multiple operators at the UV scale and find it could change the constraints on SMEFT operators by several orders of magnitude compared with when only one operator is considered. Furthermore, we find that accelerator and reactor neutrino experiments are sensitive to different SMEFT operators, which highlights the complementarity of the two experiment types.