Mass limits for  Neutrino Physics  Prospects of WIMP Direct

    
Neutrino Masses

The neutrino flavours $\nu_e$, $\nu_\mu$, and $\nu_\tau$ are defined as weak eigenstates which couple with unit strength to e, $\mu$, and $\tau$, respectively. These weak eigenstates are not, in general, states of definite mass, but instead are linear combinations of mass eigenstates , (i = 1,2,3), hence . Here, the unitary matrix U_li describes the mixing strength of mass eigenstates to the corresponding left-handed weak eigenstate. This ansatz is in close analogy to the experimentally observed weak mixing in the quark sector.