  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.
