Poster Summary: Searching for Supernova Neutrinos with Dark Matter Detectors
(by Andrea Gallo Rosso) The study of neutrinos emitted from core-collapse supernovae is a unique opportunity to investigate physics of the gravitational collapse of massive objects. When the next (galactic) supernova event will occur, electron antineutrinos will be surely measured with huge statistics by conventional detectors based on water or hydrocarbon. Although the information they can give is useful for many purposes (e.g. timing) it is not fully sufficient: detection of the other flavors is fundamental in order to reduce the systematic uncertainty on the information obtainable by the charged-current channel alone. It comes, for example, from the lack of information about the initial energy distribution and the oscillation mechanism.
Detectors aiming at rare processes – such as WIMP dark matter and neutrinoless double beta decay search – offer us an interesting opportunity in this sense. Their large active mass, low background and the same kinematics response to WIMP and supernova neutrinos make them able to detect neutral current neutrino events due to the coherent interaction with the nucleus. In the poster (see details therein) we discuss the cross section, the emission hypotheses and then calculate the number of expected events for 1 ton of target material, as a function of the detector threshold. As shown in Fig. 1 (right), the latter parameter is crucial.
Unfortunately, even if within of reach of the detector, lowering the threshold for continuous data taking experiments increases the background rate to an unsustainable level. As a solution, we propose to collect sub-threshold data stored in a circular-buffer for a certain amount of time, and then saved depending upon an external trigger given by conventional supernova detector, as outlined in Fig. 2.
The Gran Sasso Laboratory is the ideal environment for this implementation: potential involved experiments – such as XENON1T or CUORE – coexist with LVD, a conventional supernova detector. It is very well-suited for the purpose, thanks to its great life time and the possibility to have a well defined time window between the supernova event and the trigger.
This cooperation between experiments can help to extend the scientific scope of both groups, to lower even more the threshold and to improve the sensitivity to neutral-current neutrino nucleus interaction, precious signal not yet detected.