M. Selvi – 17 th June 2005 – Round Table in honour of prof. Koshiba e e x Supernova neutrino detection: present status and new ideas Marco Selvi Bologna University & INFN

M. Selvi – 17 th June 2005 – Round Table in honour of prof. Koshiba e e x Detectors for stellar collapse ExperimentMass (t)TargetLaboratoryMain channel Super-Kamiokande32000H2OH2OKamioka ee SNO1400, 1000H 2 O, D 2 OSudbury ee LVD1000“H n C 2n+2 ” + FeLNGS ee KamLAND1000“H n C 2n+2 ”Kamioka ee MiniBoone500“H n C 2n+2 ”FermiLab ee Baksan330“H n C 2n+2 ”Russia ee Others approved detector in costruction: Borexino (300 t of C 9 H 12 ), Icarus (600 t of LAr) ( AMANDA may observe a statistical enhance in the PM counting rate).

M. Selvi – 17 th June 2005 – Round Table in honour of prof. Koshiba e e x Neutrino oscillations in SN We consider the system of 3 active neutrinos f =( e,    ), mixed in vacuum such that f =U m where m =( 1,    ) is the vector of mass eigenstates and U is the mixing matrix. If neutrinos have mass they could oscillate between flavors. The oscillation is resonantly enhanced if a flavor-asymmetric medium is present (MSW matter effect). The medium density  res for the resonance to occur depends on the oscillation parameters. The wide range of density values in the SN matter allows for 2 resonance levels.  (g/cc)MediumOsc. parameters involved HH 10 3 –10 4 He“ATM” (  m 2 atm, U e3 2 ). LL 10–30H“MSW LMA”  m 2 sol, U e2 2 ) The resonance is expected for or depending on the mass hierarchy (=sign of  m 2 atm ) sign of  m 2 atm Resonance in + (normal hierarchy) - (inverted hierarchy) in LVD

M. Selvi – 17 th June 2005 – Round Table in honour of prof. Koshiba e e x “New” ideas in the market Adding a small amount of Gd (100 t of GdCl 3 in SK) in a water Čerenkov. e + p  n + e + allows the detection of both the interaction product: clear e detection through e + 16 O  16 F + e - interactions SN relic neutrinos neutrino proton elastic scattering x + p  x + p in low energy threshold detectors electron detection in liquid argon e + 40 Ar  40 K + e - electron detection in iron e + 56 Fe  56 Co + e - electron detection in lead-scintillator calorimeter ADONIS -Fe

M. Selvi – 17 th June 2005 – Round Table in honour of prof. Koshiba e e x SNEWS Main goals: Improve the trigger sensitivity for a SN core collapse by correlating the signals of two or more detectors Promptly alert the astronomy community