Neutrino bursts from gravitational stellar collapses with LVD

Abstract

Abstract. The main goal of the Large Volume Detector (LVD), in the INFN Gran Sasso National Laboratory (Italy), is the study of neutrino bursts from gravitational stellar collapses in the Milky Way. Both the detector and the data analysis procedure have been actually optimized for this purpose. Moreover the modularity of the apparatus allows to obtain a duty cycle that is very close to 100%, so that the experiment is continuously monitoring the Galaxy.The search for Supernova neutrino signal is performed online, within fixed duration time windows (20 s), and offline with variable duration time windows from few ms up to 200 s. In both cases, LVD is able to disentangle a cluster of neutrino signals from the background fluctuations, and its sensitivity extends to the whole Galaxy.No candidates have been detected during almost 18 years of observation (6013 days of lifetime): the resulting 90% c.l. upper limit to the rate of gravitational stellar collapses in the Galaxy is 0.14 events/year. Detector performances, search method and data results are here reported.

Search for Supernova Neutrino Bursts with the Large Volume Detector

“…Energy equipartition and normal mass hierarchy for neutrino oscillations are assumed. If we set the distance of the collapsing star to D =10 kpc, we get that a total of 300 events (260 at E ν ≥ 10 MeV) are expected in LVD with a 1 kt active mass, 88% of which are due to IBD (see details in [12]).…”