Heavy Majorana neutrinos in e+e- colliders

Abstract

We investigate possibilities for detecting heavy Majorana neutrinos ($N$'s) in $e^{+}{e}^{-}$ at LEP200 and future Linear Colliders. We concentrate on the processes where the pairs of intermediate heavy $N$'s produce a clear signal of total lepton number violation ($e^{+}{e}^{-}\to NN\to W^{+}{l}^{-}{W}^{+}{l}^{\prime -}$). Such a signal is not possible if the heavy neutrinos are of Dirac nature. Our approach is general in the sense that the intermediate $N$'s can be either on shell or off shell. Discussion of the relative numerical importance of the $s$ and the $t+u$ channels of the $NN$ production is also included.

Comments: 11 pages, latex (revtex), 4 eps-figures, text slightly modified, appears in Physical Review Letters (June 7, 1999, issue)