  It is shown that neutrino oscillation and Majorana type neutrino are not
compatible with Special Theory of Relativity. Instead of the Majorana type
neutrino, traditional neutrino(no rest mass) is considered with additional
assumptions that right-handed neutrino and left-handed antineutrino exist in
nature and naturally thus parity is conserved. Besides, neutrino itself is
considered as longitudinal vacuum-string oscillations. To explain parity
conservation, W+(W-) bosons are suggested as momentary interacting states
between positron (electron) and virtual-positive(negative)-charge strings,
respectively. With these postulations, an alternative explanation is also
suggested for solar neutrino problem.
