Constraining the total neutrino mass in cosmology.

• Sylvain Gouyou Beauchamps (CPPM)

The mass of the neutrino is one of the last missing pieces of the standard model of particle physics. While experiments measuring the neutrino oscillation between their flavour states can put tight constraints on the squared mass differences (Super Kamiokande, SNO, T2K...), other laboratory experiments performing kinetic measure of the neutrino mass (KATRIN) are still struggling to improve the constraints on the absolute scale of the neutrino masses. On the other hand as the universe is filled with cosmological neutrino and because neutrino have non zero, but tiny, mass, they participate to the evolution of cold dark matter density perturbations at the origin of the Large Scale Structure. In consequence, the estimation of statistics in the LSS such as the power spectrum, allow cosmologist to have an indirect constraint on the sum of the 3 neutrino mass which is 10 times better than the one from direct kinetic measurements. Future large scale survey of the sky like Euclid will potentially bring the finest measure of the total neutrino mass, allowing to distinguish between the normal and inverted mass hierarchy.

Cetacean sounds detection with KM3NeT hydrophones

• Carlo Guidi

Several species of cetaceans emit sounds to orient themselves in their movements and to locate their preys. In particular, dolphins and sperm whales emit very intense clicks in specific frequency ranges. The KM3NeT underwater telescope for cosmic neutrinos has a certain number of hydrophones, useful for knowing with great accuracy the position of all the detector's photomultipliers. These hydrophones can also be used to detect the clicks of cetaceans, in order to monitor their presence in the area and set up a tracking system for the position and movements of these animals. Currently three hydrophones and several piezoelectric sensors are working in the experiment and numerous cetacean clicks have been detected, in particular between April and May and during the summer of 2020. A preliminary analysis of these detected sounds and a description of the program to identify the clicks are presented.