Neutrino backgrounds in matter-wave interferometry: implications for dark matter searches and beyond-Standard Model physics

TL;DR

This work develops a comprehensive theoretical framework to quantify neutrino-induced decoherence in matter-wave interferometry across three coherence regimes, leveraging CνB, solar, and reactor neutrino fluxes. It shows that Standard Model neutrino backgrounds are negligible for proposed experiments like MAQRO and Pino, while light Z' mediator scenarios yield competitive BSM constraints, notably $g_ν g_n \lesssim 10^{-17}$ for $M_{Z'} \lesssim 1\,$eV from CνB. The analysis provides explicit cross-section formulations, flux integrals, and angular treatments that map neutrino energy to coherence scales, enabling interpretation of interferometer signals in terms of neutrino interaction physics. This framework positions matter-wave interferometry as a powerful probe for BSM neutrino interactions and potentially for direct CνB detection under favorable mediator scenarios, with clear paths for experimental and theoretical enhancements. The results thus offer a principled route to constrain or discover new neutrino physics using macroscopic quantum systems.

Abstract

We present a comprehensive theoretical analysis of neutrino-induced decoherence in macroscopic matter-wave interferometry experiments designed to search for dark matter and beyond-Standard Model physics. Our calculation includes contributions from the cosmic neutrino background (C$ν$B), solar neutrinos, and reactor antineutrinos, accounting for coherent scattering processes across nuclear, atomic, and macroscopic length scales. Within the Standard Model, we find negligible decoherence rates for planned experiments such as MAQRO ($s/σ_s \sim 10^{-27}$) and terrestrial interferometers like Pino ($s/σ_s \sim 10^{-22}$). However, these experiments achieve competitive sensitivity to beyond-Standard Model physics through light vector mediator interactions, with C$ν$B constraining coupling products to $g_νg_n \lesssim 10^{-17}$ for $Z'$ masses below 1 eV. Our results provide a theoretical framework for interpreting matter-wave interferometry measurements in terms of neutrino interaction physics and for deriving constraints on BSM models from experimental data.

Figures (2)

• Figure 1: Differential neutrino fluxes considered in this analysis spanning nearly eight orders of magnitude in energy. The cosmic neutrino background (C$\nu$B) shows contributions from three mass eigenstates: $m_1 = 0$ (continuous spectrum) and $m_2, m_3$ (sharp features at $E = m_\nu$). Solar neutrinos include both nuclear fusion (pp, CNO) and thermal atmospheric components. Reactor antineutrinos are normalized to 1 GW$_{\text{th}}$ at 100 m distance. Each source naturally accesses different coherent interaction regimes based on the energy-dependent coherence condition $|\mathbf{q}|r \lesssim 1$.
• Figure 2: Region in the model parameter space ($g_\nu g_n$ vs $M_{Z'}$) for which $s/\sigma^T_s=1$ in the Pino interferometer for a light $Z'$ model. The shaded region shows the parameter space where the decoherence signal would be detectable. For comparison, existing constraints from fifth force searches and equivalence principle tests are also shown, assuming a neutrinophilic $Z'$ scenario.