# Exploring low-energy neutrino physics with the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

## TL;DR

The CONNIE experiment uses advanced CCD detectors near a nuclear reactor to measure low-energy neutrino interactions, setting new sensitivity limits and exploring nonstandard neutrino physics at unprecedented low recoil energies.

## Contribution

First deployment of CCDs for reactor neutrino detection at low energies, establishing new sensitivity limits and constraining nonstandard neutrino interactions.

## Key findings

- No excess neutrino events detected at 1 keV recoil energy.
- Set a 95% confidence limit at 40 times the standard model event rate.
- Achieved world record sensitivity for low-energy neutrino detection.

## Abstract

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charge-coupled devices (CCDs) with the goal of measuring low-energy recoils from coherent elastic scattering (CE$\nu$NS) of reactor antineutrinos with silicon nuclei and testing nonstandard neutrino interactions (NSI). We report here the first results of the detector array deployed in 2016, considering an active mass 47.6 g (8 CCDs), which is operating at a distance of 30 m from the core of the Angra 2 nuclear reactor, with a thermal power of 3.8 GW. A search for neutrino events is performed by comparing data collected with reactor on (2.1 kg-day) and reactor off (1.6 kg-day). The results show no excess in the reactor-on data, reaching the world record sensitivity down to recoil energies of about 1 keV (0.1 keV electron-equivalent). A 95% confidence level limit for new physics is established at an event rate of 40 times the one expected from the standard model at this energy scale. The results presented here provide a new window to low-energy neutrino physics, allowing one to explore for the first time the energies accessible through the low threshold of CCDs. They will lead to new constrains on NSI from the CE$\nu$NS of antineutrinos from nuclear reactors.