The CONNIE experiment: upgrade and latest results

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) is a neutrino experiment located at a distance of 30 m from the Angra 2 nuclear reactor (3.8 GWth) in Brazil. It uses low-noise, fully depleted charge-coupled devices (CCDs) to detect sub-keV energy recoils from CEνNS (coherent elastic neutrino-nucleus scattering) with silicon nuclei. The experiment has been active since 2016, maintaining a noise below 2 e− RMS with an active mass of ~50 g. The results derived from the data accumulated during the 2016–2018 run, with the reactor on and off, set a 95 C.L on the CEνNS signal. They were used to impose limits on the NSI parameters, which are competitive in the lower mass region of light neutral mediators. The experiment has been upgraded to host 2 skipper CCD sensors, it has been operating for ~4 months with these new generation detectors, achieving a noise lower than 0.2 e− RMS. Here, we report the latest results of CONNIE before the upgrade, based on the analysis of data collected in 2019, with an increased signal-to-noise ratio thanks to a different (1 x 5) binning in one direction. We also present the current status of the experiment and give an overview of the upcoming year of operations.