**R.Plaga ^{1}
Max-Planck-Institut für Physik (Werner-Heisenberg-Institut)
Föhringer Ring 6
D-80805 München, Germany
**

It is shown that a Majorana neutrino with identical
phenomenology as a standard-model
Weyl neutrino obeys a Lagrangian
different by a factor in the weak-interaction term
from the one that follows from the standard
model. Assuming that the standard model *does* hold
in good approximation for the weak interactions of
a Majorana neutrino e.g. a charged-current production
cross section a factor 2 larger
than the observed one is predicted.
From this it is concluded that the neutrino is not of Majorana type.
This conclusion does *not* forbid the possible existence
of a Weyl neutrino with a Majorana mass term
and ensuing lepton-number violating phenomena (like
e.g. neutrino-less double beta decay).
The paper is not in contradiction with any published
literature, because it analyses
the formal proof of equivalence between Weyl and Majorana
neutrino for the first time under the assumption that
the standard model is *quantitatively*
correct for the weak interactions of the neutrino.

- Introduction
- The definition of a Majorana-neutrino field
- The unitary equivalence of Weyl and Majorana neutrino fields, also called ``Dirac-Majorana confusion theorem''
- Proof that L L
- Weyl neutrinos with Majorana masses
- Summary
- Bibliography
- About this document ...