It is possible to say that "a neutrino" is only a theoretical unity interpreted out of a collection of detected properties assumably resultant of disintegration of better understood forms of energy, things that more literally fit the description 'particle'.
If so, a neutrino, and this goes for more subatomic definitions, is to be understood, if we are aiming for epistemic exactness, a case of transfer of information. I.e., parts of what we may define as a particle -- empirical results amounting to almost a particle.
What kind of structural consistency does a neutrino have? It does not respond to electromagnetism, only weak-forces affect it.
It may exist only as our assumption, its structural integrity may be a fiction, an inference made because of the assumption that all change detected must be the effect of particles, which is how we still understand quanta.
It may not be the case that the transferred energy amounting to the detected neutrino is caused to be measured by it being there as such, separate from the measurement. It may be that the qualities that amount to the definition 'neutrino' are in part 'teleported', by the very expectation of and preparation for the 'arrival'.
A neutrino may in part be caused ( in terms of space-time consistency ) by the placement of the receptive material, the terms of its being-measured, which accounts for its existence. The neutrino can not positively affect, the conditions for its existence must be created. Part of the work of its being is done for it -- this may account for the lack of space-time momentum -- it is in part a non-entity, appearing here and there as 'real', actively constant particles permit it.