INVERSE NEUTRINOLESS DOUBLE-BETA DECAY REEXAMINED

We critically reexamine the prospects for the observation of the Delta L=2 lepton-number-violating process e(-)e(-)-->W-W- using the e(-)e(- ) option of a high-energy e(+)e(-) collider (NLC). We find that, excep t in the most contrived scenarios, constraints from neutrinoless doubl e beta decay render the process unobservable at an NLC of root s<2 TeV . Other Delta L=2 processes such as gamma gamma-->ll(+)W(-)W(-), e(-)g amma-->nu(e)l(-)l(-)W(+), e(-)e(-) -->nu(e) nu(e)l(-)l(-) (l=mu,tau), and e(-)gamma-->e(+)W(-)W(-), which use various options of the NLC, re quire a root s of at least 4 TeV for observability. [S0556-2821(96)006 11-X].