Hi RAZD,
you asked, "conversely is it possible for a human to live without being self-aware?"
Well, there are people with brain damage or disease who live like that as a consequence of losing brain function, but I don't think that is what you are asking. Antonio Damasio's books include discussion along those lines.
Two further sources if you haven't read them. This first book is wild but brilliant theorizing and a tour de force by Julian Jaynes:
The Origins of Consciousness in the Breakdown of the BiCameral Mind.
I just googled on Jaynes to check the title. Looks like some interesting sites out there I'll have to check out. Anyway, the books is brilliant and full of insights but I don't see how it's provable. Nevertheless its worth the read because of the scope and depth of his insights.
The other book is by Bernadette Roberts and is called:
The Experience of No Self.
This is a small book and one in which she does a good job of conveying that which can't be conveyed. She is a contemporary living in the US.
And as a result of her contemplation she reached the stage where the self dropped away. Her Catholic training in a convent was not sufficient to explain her experience to her. She finally found in a statement attributed to the Buddha confirmation of her experience. She did not become a Buddhist, but remains a Catholic. Zen of course is a sect or school of Buddhism and the core of Buddhism is Gautama Siddhartha's Awakening. Roberts does a great job of using western language and concepts to talk about her awakening experience.
Roberts and Krishnamurti may be closer to your question about living without self awareness. Since you have Zen in your name I suspect you are interested in non duality. If there is a self there is not-self or other. Roberts is writing about what happens when the self disappears and All That Is is the subject there no longer being an object. Her experiences are very Buddhist but she remains Christian.
I found both of these books in my local library.
lfen