Search for light sterile neutrinos with ANTARES and KM3NeT/ORCA telescopes A. Domi1,2, J. A. B. Coelho3, T. Thakore4, for the ANTARES and KM3NeT Collaborations 1 Università degli Studi di Genova, Genoa (Italy) -
[email protected] 2 INFN-Genova, Genoa (Italy) 3 LAL, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay (France) -
[email protected] 4 University of Cincinnati, Ohio (United States) -
[email protected] VLVnT Workshop - 19/05/2021 1 Where are we with light sterile neutrinos? • Majority of experiments have confirmed the 3 flavour neutrino oscillations. • In parallel, anomalies observed in some oscillation experiments: Anomalies in Short baseline (SBL) Ref: Prog.Part.Nucl.Phys. 111 (2020) 103736 experiments •LSND: �� -> �e •MINIBooNE: �� -> �e / �� -> �e Gallium Anomalies: �e disappearance Reactor anomalies: e disappearance � Disagreement between appearance and disappearance NO ANOMALIES observed in / disappearance. Further observations needed! �� �� 2 Where are we with light sterile neutrinos? Cosmology • Constrains the effective number of relativistic species (Neff) in our universe. • A SBL neutrino would require Neff=4. • Measured Neff compatible with 3. -> Tension with SBL anomalies. • Tension relaxes when cosmological data are combined with astrophysical data. • Cosmological data alone can be compatible with • an eV-mass sterile neutrino only if its contribution to Neff is very small, • a larger Neff only if it comes from a nearly massless sterile particle. We need further observations: neutrino telescopes make it possible! 3 Sterile Neutrinos • Oscillations in the presence of sterile neutrinos are solutions of: 2 • Adding one sterile neutrino introduces 6 more free parameters: �m41 , 3 mixing angles (�14,�24,�34) and 2 more CP phases (�14, �24).