Constraint on anomalous 4 nu interaction

The features of a hypothetical 4 interaction considered as the possible rea son for massive-neutrino instability required in the cosmological scenario that involve neutrino dark matter ire discussed. New constraints on the 4 n u -interaction constant G chi are obtained: G chi < (15-42) G(F) for m<chi> > m(Z) (G(F) is the Fermi constant of weak interaction; m chi is the mass of the 4 nu -interaction gauge boson, also known as chi boson; and m(Z) is the Z-boson mass)and G chi < (2.8-5.6) G(F) for m<chi> < m(Z). These constr aints virtually rule out the 4<nu> interaction as a possible version of sol ution to the cosmological neutrino-instability problem. (C) 2001 MAIK "Nauk a/Interperiodica".